Clean water in 1842, food safety in 1906, a ban on lead-based paint in 1971. These sweeping public health reforms transformed not just our environment but expectations for what governments can do.
Now it’s time to do the same for indoor air quality, according to a group of 39 scientists. In a manifesto of sorts published on Thursday in the journal Science, the researchers called for a “paradigm shift” in how citizens and government officials think about the quality of the air we breathe indoors.
The timing of the scientists’ call to action coincides with the nation’s large-scale reopening as coronavirus cases steeply decline: Americans are anxiously facing a return to offices, schools, restaurants and theaters — exactly the type of crowded indoor spaces in which the coronavirus is thought to thrive.
There is little doubt now that the coronavirus can linger in the air indoors, floating far beyond the recommended six feet of distance, the experts declared. The accumulating research puts the onus on policymakers and building engineers to provide clean air in public buildings and to minimize the risk of respiratory infections, they said.
new workplace standards for air quality, but the scientists maintained that the remedies do not have to be onerous. Air quality in buildings can be improved with a few simple fixes, they said: adding filters to existing ventilation systems, using portable air cleaners and ultraviolet lights — or even just opening the windows where possible.
Dr. Morawska led a group of 239 scientists who last year called on the World Health Organization to acknowledge that the coronavirus can spread in tiny droplets, or aerosols, that drift through the air. The W.H.O. had insisted that the virus spreads only in larger, heavier droplets and by touching contaminated surfaces, contradicting its own 2014 rule to assume all new viruses are airborne.
The W.H.O. conceded on July 9 that transmission of the virus by aerosols could be responsible for “outbreaks of Covid-19 reported in some closed settings, such as restaurants, nightclubs, places of worship or places of work where people may be shouting, talking or singing,” but only at short range.
detailed 10 lines of evidence that support the importance of airborne transmission indoors.
On April 30, the W.H.O. inched forward and allowed that in poorly ventilated spaces, aerosols “may remain suspended in the air or travel farther than 1 meter (long-range).” The Centers for Disease Control and Prevention, which had also been slow to update its guidelines, recognized last week that the virus can be inhaled indoors, even when a person is more than six feet away from an infected individual.
“They have ended up in a much better, more scientifically defensible place,” said Linsey Marr, an expert in airborne viruses at Virginia Tech, and a signatory to the letter.
“It would be helpful if they were to undertake a public service messaging campaign to publicize this change more broadly,” especially in parts of the world where the virus is surging, she said. For example, in some East Asian countries, stacked toilet systems could transport the virus between floors of a multistory building, she noted.
More research is also needed on how the virus moves indoors. Researchers at the Department of Energy’s Pacific Northwest National Laboratory modeled the flow of aerosol-size particles after a person has had a five-minute coughing bout in one room of a three-room office with a central ventilation system. Clean outdoor air and air filters both cut down the flow of particles in that room, the scientists reported in April.
But rapid air exchanges — more than 12 in an hour — can propel particles into connected rooms, much as secondhand smoke can waft into lower levels or nearby rooms.