The question, then, isn’t whether the coronavirus is “airborne” in the tediously academic way the word has been defined. As the journalist Roxanne Khamsi puts it, the virus is “definitely borne by air.” The better questions are: How far does the virus move? And is it stable and concentrated enough at the end of its journey to harm someone’s health?

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A handful of studies have offered preliminary answers. One team of researchers blasted virus-laden fluids into a rotating cylinder to create a cloud of aerosols. They found that the virus remained stable for several hours within that cloud, raising fears about its ability to persist in ambient air. But as the researchers have noted, the study’s experimental setup was artificial. It doesn’t reflect “what’s occurring when you’re just walking down the street,” says Saskia Popescu of George Mason University, who specializes in infection control and who was not involved in the study. “It’s more akin to medically invasive procedures like intubation, which run the risk of aerosolizing the virus, and are unique to the health-care setting.”

A second study suggests that the coronavirus can be released into the air in less dramatic ways. Joshua Santarpia and his colleagues at the University of Nebraska Medical Center found traces of the coronavirus’s RNA—its genetic material—in rooms occupied by a total of 13 COVID-19 patients, most of whom had only mild symptoms. The RNA was on obvious places such as bed rails and toilets, but also on harder-to-reach spots such as ventilation grates, window ledges, and the floors beneath the beds. The RNA even lingered in the air; using air-samplers, the team detected viral RNA floating more than six feet away from the patients, and even in the hallways just outside the patients’ rooms.

This isn’t necessarily cause for alarm. Finding viral RNA is like finding a fingerprint at a crime scene—the culprit was once there, but might be long gone. So far, the Nebraska team has failed to detect live, infectious virus in its air samples. Santarpia told me that further tests are under way, and results will be released soon.

If the Nebraska team does find infectious particles, it would mean that even mildly symptomatic people can expel SARS-CoV-2 into the air, and that the virus can travel at least the length of a hospital room—a claim supported by a few other studies. Even that, though, would not guarantee danger. Are those far-spreading virus particles concentrated enough to infect another person in the same room? How many virus particles does it even take to launch an infection? How far does the virus travel in outdoor spaces, or in other indoor settings? Have these airborne movements affected the course of the pandemic?

These questions have no answers yet. To get those answers, “you’d have to expose animals to different quantities of airborne viruses, see if they get infected, and relate that to measures of the virus [in places] where people are infected,” says Bill Hanage, an epidemiologist at Harvard. “This is the type of stuff people will work on for years, but no one is going to find out for the moment.”