One day in March the children were there. The next day nobody was there. Then, on a Saturday in August, a man came into an empty Boston suburban public school with a container of dry ice and tried to figure out how to get the students back to their desks.
Since January this man, Joseph Allen, a professor at the Harvard School of Public Health, has been saying to anyone who hears that air – the stuff everyone breathes and no one thinks about – has to move. Before the lockdown, his lab's whiteboard was full of notes about how the SARS-CoV-2 coronavirus could spread indoors. Trapped at home, he wrote tons of comments, spoke to journalists and was one of the scientists reviewing an open letter to the World Health Organization demanding that the virus could be spread through tiny airborne particles.
With the waving dry ice plumes, Allen, his team, and the school's maintenance staff conducted experiments to measure airflow in various buildings. If Everyone has something to say about this, you might see a fan with a wrinkled white HEPA filter in some classrooms this fall. Ventilation systems can also be equipped with filters in the walls. As long as the weather permits, windows are opened and wedding tents are set up in fields, while school administrations focus on what appears to be a simple and overwhelming task: moving the air. Filter it. Dilute it.
While physical distancing and wearing masks help reduce transmission via larger droplets, ventilation and filtration, which reduce the concentration of the airborne virus, are also key to improving indoor safety when airborne transmission .
Allen, who worked as a safe building advisor prior to entering academia, has helped schools, universities and daycare centers work out plans for their reopening. “Very often I get the comment: 'Oh! You are the first person we hear talk about ventilation! "Says everyone." This is deeply worrying. "
The pandemic highlights a problem Allen and his colleagues have known about for years, but most others have no idea: Schools are chronically under-ventilated. A commonly used standard for air movement is that at least 15 cubic feet per minute (cfm) per person should flow into a classroom. Allen says he recommends 30 cfm for Covid prevention. However, studies show that many American classrooms have an average ventilation rate of only 6 to 11 cfm per person.
Even if a pandemic doesn't happen, that's not good, as extensive research suggests that better airflow correlates with increased test scores and decreased absences. At least one study of air filters in classrooms also found an increase in student performance.
The maintenance and supply of air, however, went out of the public consciousness long ago. As autumn approached, Allen and his colleagues published a detailed report on how to open schools more safely and provided guidance to those who contacted them. "The problem is that we've gotten lost over the years," says Allen.
It took a global pandemic to get us to pay attention to the air that children breathe.
When it came Airflow was a top priority when designing buildings. After much of the British Parliament building, the Palace of Westminster, burned down in 1834, David Boswell Reid, a doctor, chemist and inventor, was asked to ventilate the new building. Members of Parliament had found the old building stuffy and the serious air pollution in London made opening a window a risky and extremely unpleasant move. Reid had developed an ingenious ventilation system for his private laboratory in Edinburgh and spent the next several years testing and perfecting his design for Parliament. His plan relied on the natural buoyancy of gases to draw air from the discussion chambers and draw in fresh air, and even used wet canvas to filter out the pollution. In the makeshift House of Commons, he installed an entire ecosystem of ducts that let out air through vents on the roof. In Reid's design for the permanent structure, towers that look like Gothic whims are actually functional tools for ventilation.
Everything you need to know about the coronavirus
Here you can find all WIRED coverage in one place, from keeping your kids entertained to the impact of this outbreak on the economy.
Keeping the air at a comfortable temperature was Reid's overriding concern, but he also tried to keep the fresh air circulating. For much of the 19th century, the prevailing theory was that diseases such as malaria and cholera were caused by miasms or "bad air". The theory has been used to explain why people got sick near swamps (today we would probably say mosquitos) and why slums fester sickness pits (we would now attribute it to poor sanitation). Yet when it came to air movement, they were up to something.