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The Magic Molekule: There has never been a better business (or planetary) climate in which to calm and stoke your anxieties about dirty air.

At the end of January, I found myself living through an acute bout of a very modern panic: fear of the air around me. Both my girlfriend and my dad, with whom we were living, had just tested positive for COVID. He felt okay, for now, but she was miserable. Somehow, I had tested negative twice. We were living in a two-bedroom apartment in Kansas City, and the patients quarantined themselves into bedrooms at opposite ends. I hunkered down in the middle, delivering food while wearing a pair of masks, opening the windows every now and then even though it was freezing, and trying to fall asleep on a pullout couch while keeping a nervous eye on the air-conditioning vents. With each cough and sneeze, it felt like only a matter of time before the droplets would come for me. 

Few things have shifted more in the pandemic than our relationship to the air around us. Breathing a year ago was a mindless act we performed 20,000 times a day, taking in a gaseous cocktail that’s four parts nitrogen and one part oxygen. Now, each breath comes with a possibility that the cocktail may be spiked with SARS-CoV-2. We buy face masks in bulk and think twice about inhaling if we pass a coughing stranger on the sidewalk. A book called Breath, about how to breathe better, was released two months into the pandemic and has been on and off the New York Times best-seller list ever since.

To help manage our apartment’s COVID outbreak, we were running a pair of air purifiers purchased from a salesman who promised they could “kill COVID.” Purifier sales were booming even before the pandemic, riding the wave of airborne misfortune spread by climate change and California’s wildfires. The pandemic sent the business into hyperdrive. Coway, a leading manufacturer, sold more purifiers in a single month, last August, than it did in all of 2017. Texas bought a thousand purifiers for its state capitol, and New York City’s public schools bought 30,000 — not enough to satisfy one group of teachers, who crowdfunded $159,000 to buy more. Last fall, as cases continued to rise and Americans contemplated a long winter indoors, the three most popular items on Wirecutter, the product-reviewing arm of the Times, were all air purifiers.

Consumers turned to Wirecutter with good reason: The purifier industry has been a swamp of misinformation and specious claims since long before there was a pandemic fortune to be made. There are now purifiers for your home, your office, and your car as well as ones you can carry like a clutch or wear as a necklace. Many manufacturers crow about their patented technologies, backed by studies of sometimes dubious quality. Beyond HEPA filters, which remain the industry standard, you can buy plasma generators, electrostatic precipitators, germicidal irradiators, needle-point bipolar ionizers, activated-carbon filters, dry-hydrogen-peroxide systems, ultraviolet lights, and a Kickstarter product made of “13 carefully selected plants known for their ability to purify the air” (never mind that experts estimate an 800-square-foot apartment would need more than a thousand plants to make any meaningful difference in air quality). Start a Google Alert for “air purifiers,” and headlines like “Estonian Tech Firm Says Wearable Air Purifier Can Kill Virus With UV Light” will arrive in your in-box every day.

It was unclear how exactly the model we bought could “kill COVID” — it was a literal black box — but, like everyone else, we had been looking for reassurance wherever we could find it. When I did a bit more research and found the device online, I discovered it was sold by a multilevel-marketing company that also hawks supplements with names like KetoneZone, a $299 bottle that infuses water with hydrogen for “anti-aging” purposes, and Re:Plenish, “a unique product” with “a proprietary blend of red grape juices” that offers the benefits of red wine without the alcohol. I pulled my mask on a little tighter.

Air-quality experts say well-made purifiers, properly deployed, can be a bulwark not only against COVID but against the increasing barrage of environmental horrors circulating in our air. Yet it’s impossible to have these conversations without hearing frustration from researchers and academics at the bold claims made by some in the industry. Among the most contentious flash points has been the ascent of Molekule, a company started by a family of scientists in Florida that now sells the most hyped purifier on the market. Backed by Silicon Valley venture capital and omnipresent on Instagram, Molekule promises revolutionary air-purification technology (photoelectrochemical oxidation, or PECO) tucked into a sleek metallic package. In an industry filled with cheap plastic boxes, the Molekule is pretty enough to impress Jony Ive, with a price and a brand ($799 for the flagship Air; $1,119 for the Air Pro; $499 for the Air Mini+) to satisfy Tim Cook.

Clean air is now the ultimate luxury, and the business proposition rests on turning a commodity we’ve never had to pay for into a premium -product. But hovering over Molekule and the rest of the purifier industry are questions coming from university labs and consumer–product testers: Do these things actually work? And how much should clean air cost? Molekule and other manufacturers would put the question back to you more urgently: Just how much is your next breath worth?

he air-purifier business emerged from various attempts to destroy ourselves. Gas-mask research from World War II was foundational to the industry, and scientists who worked on the Manhattan Project had to figure out how to sequester radioactive dust while they built the atomic bomb. The filters that emerged from that work led to a standard — “high-efficiency particulate air,” or HEPA — that remains the dominant one today.

HEPA filters are mats of fibers, several inches thick, with billions of tiny gaps of varying microscopic diameters between them. They function less like a colander and more like a three-dimensional maze. Large particles, such as dust and pollen, crash like mosquitoes flying into a screen door. Smaller particles — a virus carried by an airborne droplet, say — may sneak around one fiber only to hit the next. HEPA filters aren’t perfect, but for most of what experts believe we should worry about, including COVID, they’re pretty close: They must capture 99.97 percent of particles that are .3 micrometers across, which is more than a hundred times narrower than a strand of human hair. Particles of this size are, paradoxically, even more difficult to catch than smaller ones thanks to principles of Brownian motion, which dictate that the tiniest particles will chaotically bounce around in their race through the filter and eventually get stuck somewhere deep in the maze.

HEPA filters are cheap, effective, and relatively straightforward to build an air purifier out of — make a fan move as much air through the filter as possible. The first commercial ones were installed in hospitals in the 1950s, and a German company began putting them into homes in the 1960s. Several major appliance manufacturers entered the market in the 1980s as consumers began to realize how our air could hurt us. Pollution and aerosols were a concern, as were the toxic gases emanating from our household products. Asthma had long been considered psychosomatic — the repressed cry of a child for its mother — but scientists now understood that stuff in the air we breathe could make it harder to breathe in the first place.

The situation hasn’t improved. The air in our homes is now up to five times dirtier than it is outside. Cheap construction has made the problem worse, as, ironically, have efforts to make buildings more energy efficient by sealing up windows and leaks, thus decreasing ventilation. That ill feeling you used to get after spending too much time in your office has a name: sick building syndrome. All of this is of particular concern because most Americans spend more than 90 percent of their day indoors — more time than many whales spend underwater.

The mold, dust, pollen, toxic gases, smoke, microbes, and other particles that fill our modern atmosphere have been linked to all kinds of problems: Alzheimer’s, ADHD, autism, blood clots, cancer, dementia, depression, diabetes, dizziness, worsening eyesight, fatigue, headaches, irritable bowel syndrome, liver damage, osteoporosis, schizophrenia, sleep apnea, throat inflammation, and increases in violent crime. Allergies are getting worse thanks to climate change, and asthma cases continue to rise, especially in the developed world, where the air is most polluted. Bad air makes you dumber and makes your employees less productive. The United Nations has declared air quality the world’s most significant environmental health risk, and the problem is worse for the poor. (The wealthy didn’t move to the hills of Los Angeles, above the smog, for the views alone.) Just because you weren’t thinking about your air before COVID doesn’t mean it wasn’t an issue; as the Environmental Protection Agency put it in 2014, each breath you take is “an opportunity to put pollutants into your lungs and body.”

The biggest thing about COVID is the fear of the unknown,” Jaya Rao, the CEO of Molekule, told me in the middle of my own personal air panic. She was on Zoom, joined in two other boxes by a pair of PR representatives; I was now two days into quarantining in a hotel room a block away from my girlfriend and my father, who encouraged me to leave so I wouldn’t get sick. (Before I left, the CEO of another air-purifier start-up had texted me some modeling that quantified the threat. “With 3 people in a 2k square foot home, 2 infected, and assuming 8 coughs per hour you have a 41% risk of infection,” he wrote, adding that one of his purifiers could cut my risk to 17 percent.) I was happy not to stress about every breath, but I was suddenly worried all the precautions had been for naught. Despite testing negative a third time, I was feeling ill and looked around my hotel room with suspicion. The windows didn’t open, and the air was stale. Everything was clean when I arrived, but the TV stand was now covered with a layer of dust, as if a light snow had fallen. When I fluffed a pillow, the air filled with tiny particles. I now knew too much and recalled an unfortunate fact I learned from Molekule’s Twitter feed, on which the company is quick to share fears you didn’t know you should have: After two years of owning a pillow, one-tenth of its weight consists of the corpses of dust mites and their excrement.

“Air is a complex space,” Rao told me, although in her family, she is a relatively recent convert to the idea. Her father, Yogi Goswami, is the director of the Clean Energy Research Center at the University of South Florida and has published 22 books and obtained 31 patents since moving to the U.S. from India in 1969. In the ’90s, Goswami developed a technique that used photocatalytic oxidation, or PCO, to decontaminate groundwater at Tyndall Air Force Base on Florida’s Gulf Coast. The sun’s UV rays hit a titanium-dioxide catalyst that oxidizes jet fuel in the water, breaking it up. Goswami compared the process to colored fabric fading in the sun.

Eventually, he wondered if the process might work on air. He had a personal stake in the idea: His son, Dilip, suffered from allergies and asthma that were so bad he sometimes ended up in the emergency room. The Goswamis tried changing Dilip’s diet and putting a HEPA filter in his bedroom, but nothing worked. In 1993, Yogi went to a conference hosted by ASHRAE, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, looking for new ideas, but he came away disappointed that HEPA filters remained the standard despite some limitations. They did nothing, for instance, to ward off volatile organic compounds, or VOC’s, which can include potentially toxic gases like toluene or formaldehyde that were becoming more and more common in cheap household products.

The industry’s first major turn away from HEPA came in 1998, when the Sharper Image, the infomercial and shopping-mall staple known for its massage chairs and nose-hair trimmers, unveiled the Ionic Breeze — an air purifier like no other. The Breeze emitted charged ions that latched on to particles passing through the device, causing them to stick. The Breeze became so popular it made up almost half of Sharper Image’s sales.

But, in 2002, Consumer Reports published testing that found the Breeze “ineffective,” claiming it produced “almost no measurable reduction in airborne particles.” The industry had developed a standard measurement known as the “clean-air delivery rate,” or CADR, which tests how well a purifier can clear pollen, dust, and smoke out of a 10.5-by-12-foot room. The higher the CADR, the better — and the Breeze’s was shockingly low. The Sharper Image criticized the test as an outdated way to measure its technology, but when the magazine redid its testing with different metrics, the Breeze flunked again. (The Sharper Image unsuccessfully sued Consumer Reports.)*

Three years later, Consumer Reports published an even more damning report: The Breeze was emitting potentially harmful amounts of ozone. The most sophisticated air purifier on the market wasn’t just bad at its job. It was making the air worse.

Meanwhile, in Florida, Yogi Goswami was trying to use UV lights and the titanium-dioxide catalyst to see if he could decontaminate the air that moved through it. While HEPA filters simply capture particles, Goswami’s goal was to oxidize, or destroy, any harmful particles. He had a prototype running at home for Dilip and licensed the technology to a company called Universal Air Technology, promising to “revolutionize our notions about the quality of indoor air” and deliver “a bullet for the bacteria.” After the post-9/11 anthrax scare, Goswami told the press that his technology would be “very effective against bioterrorism” and that Bill Nelson, a U.S. senator from Florida at the time, wanted to install it in the Capitol mailroom.

But while PCO technology was effective in a lab, it was difficult to calibrate in practice. UV lights are very good at decontaminating surfaces, where movement isn’t an issue, but applying the technology to fast-moving air was a challenge. The PCO process was too inefficient to work effectively, and worse, could produce the same by-products as the Ionic Breeze. Goswami spent the next decade trying to make the technology work better. He eventually gave the updated process a new name — photoelectrochemical oxidation — and started testing a new prototype on his own grown kids: Dilip reported that it alleviated his allergies, while Jaya thought it helped with her migraines. It wasn’t clinical science, but it was a start. Both Dilip and Jaya graduated with master’s degrees in engineering from Stanford, and in 2014 the Goswamis decided to start a business selling Yogi’s technology. They called it Transformair. “A lot of it was noble intention — this vision of improving the world’s air,” Marc Sokol, an early investor in and adviser to the company, told me. “For a founding team, they were the least mercenary I’ve met in a long time.”

But it was hard to raise start-up capital in Florida, and in 2015, Dilip and Jaya moved Transformair to the Bay Area. Silicon Valley was in the middle of a tech-enabled-hardware bubble: Nest was disrupting home thermostats, while Jawbone, a speaker and wearables company, had a $3 billion valuation — two years before liquidating all its assets.

The Goswamis were focused primarily on installing Transformair’s technology into HVAC systems, where airflow can be regulated and potential dangers controlled, but their advisers at a start-up accelerator in San Francisco encouraged them to build a consumer product instead. “Once they started pitching these early-stage funds in San Francisco, they were much more focused on building the big-picture billion-dollar company that could sell a million devices,” Sokol said.

The company raised $3.75 million from several investors, including Jeff Clavier, an early backer of Fitbit who told me he believed the company had a chance to deliver “a Fitbit-like outcome or more.” While he could sell a person only one Fitbit, he could potentially sell them an air purifier for every room in their home. Dilip later told a reporter that the company’s “total addressable market,” or TAM — a venture-capital metric for assessing how big a company’s market can be — could more than match the ambition of the era: “Our TAM is global air.”

The trick to selling an air purifier is persuading people to spend money for a benefit they can’t see. Another issue is getting them to live with a device that, of necessity, is often noisy and ugly. The core components of an effective purifier are the size of its filter and how much air moves through it, which means purifiers are often bulky and equipped with loud fans. The aesthetic problem is also a practical concern: They are most effective in the middle of a room, not shoved into a corner.

The Goswamis wanted Transformair to look different. “We wanted to signal that it’s a product you should be proud of,” Jaya told me. The company’s first hire in San Francisco was Peter Riering-Czekalla, a German designer who had previously worked at IDEO; he was tasked with fitting the Transformair into an attractive package. The device had a prefilter to capture larger particles, after which another filter utilizing Yogi’s photo-electrochemical-oxidation process could do its work on whatever got through. One early prototype was an ominous black box. Another looked like a metal nightstand dreamed up by an Ikea designer in a particularly dark mood.

Eventually, Riering-Czekalla found a look unlike anything on the purifier market: a slender two-foot-tall cylinder with sharp edges on top and a buttery-soft handle made of vegan leather that complemented the MacBook-silver casing. It was a device that would be at home in an Apple Store and sell well in a home-goods shop in Greenpoint.

A product this alluring needed a better brand. Transformair was explicative but unremarkable in an industry that leans heavily on its most obvious reference. (A very partial list of purifiers could begin with Airdog, Airfree, Airocide, AirTamer, and Airthereal — followed by Blueair, FrescheAir, IQAir, and Vectair.) The company brought in a branding team led by Marc Shillum, who had given names to Barnes & Noble’s Nook and HBO Go, in the first of three attempts at branding the network’s streaming service. “I said to them, ‘Listen, I’m not sure, in this category, that science is going to cut through,’ ” Shillum told me. “There are loads of claims, and people don’t like thinking about all of it. Customers want a product that works, and they want to get on with life.”

In 2016, the Goswamis unveiled Molekule, with the k inserted not only for koolness but as a reference to the letter’s notational stand-in for the reaction rate in chemistry. The brand was perfectly tailored to a certain type of consumer: It had groundbreaking technological claims, haute design, and a pile of VC cash to spend on Instagram ads. The company’s press team pitched tech sites and “high-value, low-risk targets”: Goop and parenting blogs. Molekule made an appearance at South by Southwest and got the MoMA Design Store to carry the device. In 2017, Time put Molekule on a list of the year’s best inventions, alongside the fidget spinner.

Molekule was riding the tailwinds of the wellness boom like CBD oil for the air, promising to alleviate a range of health issues even if you weren’t quite sure how. Jaya bragged to me that Tom Brady’s manager had reached out about getting a Molekule, and Dilip said he wanted consumers to think of the brand “in the same way we think of organic food or yoga.” On Shillum’s recommendation, Molekule described itself as more than an air purifier. It was “a catalyst for human progress.”

The company’s big break came in the fall of 2018, when California started to burn. Wildfire smoke is loaded not only with soot but with toxins that are shed from houses, asphalt, and other manmade structures as the flames tear through. As the blaze continued, a Molekule street team handed out N95 masks in front of a BART station and gave free machines to fire departments. Molekule targeted Californians with Instagram ads featuring the Golden Gate Bridge obscured by smoke. Some locals were offended, but others were primed to embrace a tech-forward, Instagrammable solution to their suddenly life-threatening situation. The company had to increase production to keep up with demand. Bobby Berk, the design expert from Queer Eye, now has three in his L.A. home.

And that was in the Before Times. Last March, as the early days of our current air panic settled in, Julie Macklowe, an entrepreneur who runs a bespoke whiskey brand, filled a U-Haul with supplies on the Upper East Side to escape the city for her home in Sagaponack: rice, Clorox wipes, and half a dozen Molekules. When I spoke to Macklowe last month, she was in Aspen, sans Molekule, but had no regrets about the thousands of dollars she spent on the devices. She had been early to air purifiers, wearing an ionizing necklace whenever she traveled, but she struggled to find one for her living room. “I tried one my dentist had, but it was so ugly I didn’t really care if it was doing anything or not,” she told me. COVID’s arrival had Macklowe and many others turning to air purifiers as much for psychological support as for any immunological benefit. “Look, I can say that we haven’t had COVID, but I’m not gonna say it’s because of the Molekules,” Macklowe said. “I’ve tried to Google to see if they work, and there’s not tons of research. But in the middle of winter, you want friends in your apartment, it’s 20 degrees out, and I think people feel psychologically better when they see it. It’s that false sense of security.”

When talking about what drives his work at Molekule, Dilip Goswami likes to cite a piece of advice from Swami Vivekananda, a 19th-century Hindu monk. “He said, ‘Just take up one idea and make that idea part of every aspect of your life. Just focus on that idea. Put all other ideas aside,’ ” Dilip has said. “For me, that idea was Molekule.” During the company’s branding exercise, Shillum argued that Molekule’s biggest obstacle was “the absolute monarchy of the HEPA filter,” as he put it to me. “HEPA’s been around 80 years,” he said. “We can say the same about the incandescent light bulb — that it works, but at what price?” Shillum suggested that photoelectrochemical oxidation needed a catchy shorthand to win this war. PECO would be the new HEPA.

Since then, the Goswamis have argued that PECO should supplant HEPA as the industry standard. More specifically, they have condemned HEPA filters at every opportunity. “These things don’t work,” Dilip told a reporter in 2019. At South by Southwest, Jaya said HEPA was “a technology that’s fundamentally failing.”

HEPA filters aren’t perfect. They don’t capture gases or mask odors (a post on Molekule’s site claims PECO is “the best solution for weed smoke”), although activated-carbon filters, which come with many HEPA-based purifiers, can help with both. Molekule’s core argument is that HEPA is a passive technology; it merely collects particles, while PECO can potentially destroy them. By Molekule’s launch, the Goswamis had lab results showing their device could help with VOC’s and didn’t release ozone. But the company was coy about its clean-air delivery rate, a metric many other companies share publicly. Particles are the No. 1 health concern for air-quality experts, and even those who see promise in Molekule’s technology have objected to the company’s attempts to erode public trust in HEPA. “I’ve had words with them about this,” said Chris Hogan, an engineering professor at the University of Minnesota who has tested Molekule’s devices. “HEPA filters work.”

Since 2015, Tim Heffernan has been in charge of testing air purifiers for Wirecutter, which has earned a devoted following for its recommendations of a single product in a particular category: “Best for Most People.” Heffernan is not an air- or water-quality expert, but that has become his primary beat, in addition to shovels and knife sharpeners. Consumer faith in the site is so strong that unsatisfying recommendations can feel like betrayals. When I spoke to Heffernan in February, parts of the internet were bashing Wirecutter’s humidifier recommendation, which he had helped make; Angela Lashbrook, an outraged customer, wrote on Medium the humidifier was “a common sight on Brooklyn sidewalks, where people leave items because they want to give them away or because they are literal garbage.”

But the site has become a go-to guide for overwhelmed online shoppers, and during the pandemic, Heffernan’s purifier recommendation took on additional weight: It was Wirecutter’s most popular review of 2020, ahead of office chairs, personal thermometers, and the Peloton. Readers were no longer coming to find the best air purifier for most people but to find, as one Wirecutter devotee put it to me, “the best air purifier for most people living through a once-in-a-generation global health crisis.”

To make his pick, Heffernan runs a test designed with the CADR metric in mind but with an eye toward how they work in the real world. He places each air purifier in either the spare bedroom of his Queens apartment or a conference room at Wirecutter’s headquarters in Long Island City and then lights five matches. (In 2018, he went to Wirecutter’s Los Angeles office and burned five sticks of sandalwood incense to simulate wildfire conditions.) The matches release millions of tiny particles, and after 30 minutes, he uses a particle counter to measure how well the devices have cleared the room.

For seven years running, Heffernan’s top purifier recommendation has been a $230 HEPA-based purifier from Coway, a Korean company. Heffernan had chosen not to test Molekule for several years, but by 2019, the hype was too loud to ignore. Molekule has more than 100,000 followers on Instagram, while Coway has only 2,600. Just before the final season of Game of Thrones, Maisie Williams, who plays Arya Stark, posted affectionately about her Molekule. (She is now an investor.)

Heffernan’s review was not kind: The Molekule Air, he wrote, was “the worst air purifier we’ve ever tested.” The company’s Air Mini was “the second-worst air purifier we have ever tested, behind — you guessed it — the other Molekule.” (The Mini has a larger prefilter, which Heffernan guesses might have helped it best the Air.) He even found that a popular DIY hack — attaching a box fan to a HEPA-like filter that you can buy at the Home Depot for a total of $40 — could outperform the Molekule in his test. Wirecutter put Molekule on a shortlist it maintains of the “Worst Things for Most People,” alongside air fryers and Keurig coffeemakers.

This was a disorienting moment for Molekule’s core demographic — its faith in aesthetics as a marker of quality coming into conflict with its devotion to the site’s curatorial abilities. Molekule tried to fight back, posting rebuttals on social media — #MoSetsTheRecordStraight — and spending a chunk of its advertising budget on Google ads atop searches for “Wirecutter air purifier.” The company complained that the site had not tested its devices’ ability to handle VOC’s and argued that a CADR-like test wasn’t a good way to judge their capabilities — the same argument the Sharper Image had made two decades earlier. Jaya called the review “clickbait.” Jeff Clavier, the Fitbit investor, told me it was “fake news.” Molekule also implied that Wirecutter was criticizing its products because it didn’t offer the affiliate links that allow Wirecutter to be paid any time someone buys something through the site.

But a month later, Consumer Reports, the nonprofit that had taken down the Ionic Breeze, published an equally critical review. Both Consumer Reports and Wirecutter zeroed in on the fact that Molekule didn’t appear to move enough air through its filters; the cylinder seemed to be too sleek for its own good. While Molekule claimed the Air was strong enough to clean a 600-square-foot room, Consumer Reports said it would recommend the device only for a space one-sixth that size.

Shortly after Wirecutter’s review appeared, Dyson, a leader in the hip-appliance space, filed a complaint with the National Advertising Division, an ad-industry watchdog, objecting to dozens of Molekule’s advertising claims. Dyson has a reputation for playing hardball, and Jaya told me she had spoken to a number of people in the vacuum world who had warned her, “Dyson will come after you, and they will drag you through the mud.” The company had previously put up a billboard next to Molekule headquarters that read, DESIGN IS ONLY TRULY BEAUTIFUL WHEN IT WORKS PROPERLY.

After investigating Dyson’s objections, the NAD released a report pushing Molekule to back off of many of its most aggressive claims, including about PECO’s superiority to HEPA filters: Molekule was told to stop using one of its taglines, “Finally, an air purifier that actually works.” The report also critiqued some of the self-published studies on Molekule’s website. Several had been conducted in a chamber the size of a cardboard box, and in certain cases, only the PECO filter was tested, not the Molekule itself. One of the authors of a paper about Molekule’s impact on asthma and allergy sufferers is Jaya’s oncologist husband. After reading another study credited to a researcher at the University of Minnesota, I noticed that a photo of the laboratory setup showed a palm tree out the window. The researcher admitted to me that the testing had taken place at Yogi Goswami’s lab at the University of South Florida.

Molekule is far from the only company in the purifier industry to self-publish research or to extrapolate narrow results into broader claims. (Wirecutter and Consumer Reports both trashed Dyson’s cool-looking purifiers, too.) “I would estimate that the air-purification industry as a whole is 50 to 75 percent illegitimate,” Jeffrey Siegel, an engineering professor at the University of Toronto who has studied purifiers for 20 years, told me. “You’re dealing with an industry that doesn’t want consumers to understand these devices and how they work.” Molekule now faces two separate class-action lawsuits, one of which cites an entire “wildfire subclass” of complainants who bought Molekules when the company was pushing its purifier as a cure for their misery.

Molekule declined to share any figures about the state of its business, but it’s safe to say the negative reviews have not prevented it from having a very good pandemic. The company raised a $58 million round of venture capital last February, pushing its fund-raising to nearly $100 million — far more than any other purifier start-up. Despite the critical reviews, many users love the company’s devices and anecdotally report that they work better than others they’ve tried. Luxury hotels, desperate to bring guests back inside, have installed them from San Francisco to Fort Lauderdale to the Ocean House in Rhode Island, where a friend was recently told at check-in that the machine in his room was “medical grade,” as if he were buying weed. At a minimum, Molekule has brought aesthetics to the industry: Coway, Wirecutter’s pick, now sells a purifier in millennial pink and has a model of its own at the MoMA Design Store.

Like every purifier-maker, Molekule leaped at the opportunity to pitch its device as a pandemic solution. Yogi told a reporter that he was “very confident that this technology will destroy coronavirus” and that he wanted to send some Molekules to China. Last February, Jaya told a reporter that the virus was “a rather simple structure for us to be able to destroy” and that she had recently flown cross-country with an Air Mini plugged in under her seat. The attention only picked up when wildfires again raged through California last fall while COVID cases continued to rise. “Our product launches tend to be pretty timely,” Dilip told Venture-Beat as Molekule announced its new Air Pro model, which promised three times as much power as the Air.

By now, every reputable purifier manufacturer has run testing to show that its device can handle COVID. HEPA filters have done well in tests, as has Molekule — although testing air purifiers’ COVID-fighting capabilities in a real-world setting is, for obvious safety reasons, impossible. Most of the air-purifier experts I spoke to have the machines in their homes for mold or pet allergies, not COVID. If a sick person comes into your home, a purifier across the room isn’t going to help.

Then again, I never tested positive for COVID — maybe our purifier had worked? More likely, I had some form of immunity or simply got lucky. In any event, the purifier we bought was recently on back order, and if the industry has learned anything from the pandemic, it’s that Marc Shillum was right: Science isn’t what sells.

Jeffrey Siegel, the University of Toronto professor, told me the volume of fly-by-night operators entering the market had increased dramatically since COVID began to spread. He had recently spoken to a woman looking to buy purifiers for a school district and pointed her to several specious claims on a company’s website that used what seemed to be language meant to obfuscate its purifier’s true capabilities. After the woman told Siegel she had asked the company about the issue, he checked the site again and discovered it was now making the same claim with different foggy language. When I got in touch with a purifier start-up called Happi that launched in December and advertised itself on Instagram as a cheaper Molekule (purifier ads now haunt me everywhere I go), the company’s founder told me he had pivoted to air purifiers from “electric rideables.” Everyone becomes a vulture when the world is burning.

With the far side of the pandemic coming into view, air-quality experts hope this will be a watershed moment in how we think about the air around us, which will be no cleaner after COVID is under control. The question is how we’ll deal with all of the problems. Max Sherman, a retired scientist at the Lawrence Berkeley National Laboratory who has studied air quality for decades, is an advocate for simple solutions: Go outside, keep toxins out of your life, increase ventilation. He sometimes gives talks as Dr. Duct Tape, a nom de plume alluding to his belief in the effectiveness of patching up leaky HVAC systems. Beyond that, HEPA filters work — Dr. Duct Tape has three air purifiers in his home — and ultraviolet technologies like PECO may develop into meaningful tools. (Last month, American manufacturer Westinghouse promised to solve the “COVID quarantine stank” emanating from our indoor lives by using a patented purification technology called nano confined catalytic oxidation, or NCCO. Look out, PECO.) Sherman had attended a webinar about Molekule’s technology and came away impressed. “As a techie, I love it,” he said. But he wasn’t ready to recommend it. Molekule simply didn’t move enough air to meet his and the industry’s standards — Air Purification 101. “It’s not going to be able to do the job unless you have a bunch of them,” he said.

That may be possible for the Julie Macklowes of the world, but it isn’t helping anyone without a few thousand dollars to spend on fresh air. Neither would the Molekule that Sherman said he would recommend: the Molekule Air Pro RX, a refrigerator-size purifier meant for medical facilities. The RX is big and bulky and comes with caster wheels rather than a vegan-leather handle. But it does move plenty of air. In the end, Dr. Duct Tape said, air purification is an ugly business.