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Can Spraying Bacteria Help You Fight Allergies?

Probiotics are the latest weapons being deployed in homes.

When it comes to fighting allergies, over-the-counter medications work for me about as well as a wet Band-Aid applied to a gaping flesh wound. After waking up to itchy eyes and a stuffy nose one too many mornings, I found myself reading about a company called BetterAir that claimed it could alleviate my symptoms using an unorthodox solution: bacteria.

BetterAir is one of several companies now selling probiotic-based cleaning products that have cropped up in places like Sears, the Skymall catalogue, and various lifestyle websites over last four years. Airbiotics, another company, sells a wide range of aerosol mists. Probiotic Power sells skin creams. Professional cleaning services are also advertising the use of probiotics to gain a competitive edge.  One of the newest and most sophisticated examples, however, is BetterAir's probiotic "ecobalancing system," a digital air purifier that automates the process of filling your home with (supposedly) healthy bacteria. Airbiotics is also working on a similar device.  At almost $300 a pop, these purifiers purportedly "clean" your home by releasing probiotics into the air. To be sure, the word purifier is a bit misleading: These devices don't actually purify the air with a filter that conventional air purifiers use. Instead, they pump "good" bacteria into the air to rebalance the ecosystem of bacteria in your house and make the air cleaner.


Unfortunately, the evidence that this process actually works is scant at best. There are currently no US-based studies that have been done to prove their effectiveness. Three of the case studies BetterAir cites on its website were conducted in partnership with a third-party testing company. The fourth was led by a group in Italy and utilized a very small sample size (11.2 microbiological samples over the course of four months).

On the other hand, I did find a few reasons to consider suspending disbelief: For the last decade, scientists have been looking for ways to combat pathogens in the places where they're most prevalent, like plumbing systems. Traditional chemical disinfectants have been unable to eradicate all of the bacteria (studies have shown that more than thirty families of bacteria have been isolated from drinking water). What's more, they've also encouraged chemically resistant super-bacteria to breed. As a result, scientists have turned to "good bacteria" for help.

One of those scientists is Amy Pruden, a professor of civil and environmental engineering at Virginia Tech. Eight years ago, Pruden was at the American Society for Microbiology Conference where she stumbled into a talk by one of the first researchers to successfully conduct a fecal transplant—a procedure that infuses bacteria from the poop of a healthy person into the gut of a sick person to improve their digestion. "I was blown away that they could do it. It showed that you can add a healthy microbiome to an existing system," said Pruden. "I came back after I went to that conference and told [my colleague,] 'This is so exciting. They're doing fecal transplants and we can do the same in drinking water.'"


Since then, Pruden and others have conducted studies that show certain bacteria, such as legionella pneumophila, which causes a serious respiratory illness called Legionnere's Disease, dwindle when other types of bacteria are added. There are several possible explanations for this: When there are many types of bacteria in a given environment, they all compete for resources so that no one type takes over. Some types of bacteria, however, can be added to kill other types of bacteria by breaking their cell membranes. Manufacturers of bacteria purification systems believe this logic can be applied to their products. "We know that a diverse bacterial and fungal community is generally associated with better health outcomes. But diversity simply by adding microorganisms is not necessarily a good thing," said Jeffrey Siegel, a professor of civil engineering at the University of Toronto who studies air purification systems. "A building with greater fungal diversity, we know that's not a healthy thing. You don't know whether that fungi is good for you or bad for you."

When I asked BetterAir what bacteria they included in their product, they declined to answer, citing proprietary information. Siegel says this is a red flag: Can they survive in your home? Is there enough bacteria released that could actually change a microbial community? How might they interact with the existing bacteria in the house? Siegel worries that inhaling unknown particles could wreak havoc for people with existing respiratory issues. People like me.

Eager to see if the product could relieve me of my allergies and asthma, I asked BetterAir to send me a device to test in my new apartment. It arrived in a sleek white package from Hollywood, Florida. I plugged it into the wall where it puffed quietly to itself every 30 minutes, presumably releasing bacteria into the air.

BetterAir representatives told me that I should feel the effects within a week. But after the seventh day had passed, I didn't detect any difference. Siegel said this could be a sign that I might already have a healthy microbiome—for one thing, I use bleach sparingly. I also welcome good bacteria into my house: I have tons of plants, and open my windows regularly.

Those are cheaper, easier solutions—and until the science catches up, I plan to stick with them. "Right now," Siegel said, "anyone who is using an air cleaner like this is a subject in an uncontrolled experiment."