It’s hard to imagine modern life without glycols. They are used in cosmetics, fog machines, and food. As you read this, you’re almost certainly wearing or drinking from something they were used to produce — polyester fabric or plastic bottles, for example. If you brush your teeth with toothpaste or top your salad with bottled dressing, you’ve come into contact with these manmade chemical compounds.
Manufactured at industrial scales from crude oil and natural gas, glycols are a common antifreeze ingredient. They are also useful for refrigeration, allowing cooling systems to maintain colder temperatures than water alone allows.
But there’s something more they could do for us: When glycols are vaporized into indoor air, they rapidly inactivate viruses, bacteria, and fungal spores — even while the glycol vapors remain at low enough concentrations to be invisible, odorless, and tasteless. It’s a property that could reduce the spread of the seasonal flu, and maybe even help stop airborne pandemics before they begin. We’ve known about their disease-fighting properties for almost a century, and new research might allow us to deploy them at scale soon.
Chemically speaking, glycols are organic compounds that belong to the alcohol family. Propylene glycol (PG), dipropylene glycol (DPG), and triethylene glycol (TEG) vapors specifically seem safe for humans to breathe. TEG vapors in particular would be cheap to deploy — costing only about 10 to 50 cents per day to protect a 1,000-square-foot room. While it’s not exactly clear how they combat pathogens, they’ve been shown to inactivate both air- and surface-borne viruses and prevent respiratory disease transmission. According to Curtis Donskey, an infectious disease physician and researcher at the Cleveland VA Medical Center, glycol vapors are particularly effective against enveloped viruses — think SARS-CoV-2, influenza, and Ebola.
There’s a body of evidence supporting their use for infection prevention dating back to the mid-20th century. One study conducted over three winters between 1941 and 1944 in a pediatric hospital demonstrated a 96 percent reduction in colds in wards that were disinfected with glycol vapors, compared to those that weren’t. Patients in the glycol-treated wards also had 90 percent fewer total cases of tracheobronchitis, middle ear infections, and acute pharyngitis than the controls.
That research is many decades old, of course, and even similar studies would employ different methodologies today. “Different times [mean] different research standards,” Jacob Swett, the executive director and founder of Blueprint Biosecurity, a nonprofit focused on pandemic prevention, told me. “But I think this shows where the potential could be.”
