New York – America’s ambivalence about wearing masks has played a part in its COVID-19 woes. But there’s another factor beginning to receive a closer look as the virus tears through some of the hottest parts of the United States: Our zealous — and rather unusual — insistence on living and working in spaces that are largely sealed off from the outdoors.
It wasn’t always so. In the 19th century, a growing number of people lived and worked in cramped, airless quarters in the nation’s growing cities. As disease ran rampant, the solution was simple: better ventilation. A growing number of medical professionals prescribed “natural disinfectants” — fresh air and sunshine — to counter the threat of disease.
In his 1882 book “How We Ought to Live,” a doctor named Joseph Edwards argued for outsized windows and doors in homes, claiming that “the larger you make your openings, the nearer will your house approach a tent.” A tent? He explained: “I am sure we would all enjoy better health, if houses were unknown, and we lived in tents or in the open air, as animal life in a state of nature is accustomed to do.”
But Edwards and other like-minded reformers were backed up by another recent discovery. During the Civil War, doctors noticed that wounded soldiers treated in open-air settings had higher rates of survival than those in cramped hospitals.
The acceptance of the germ theory of disease helped buttress these prescriptions. In time, medical advice helped drive reforms instituted in the nation’s cities. In 1901, the New York State Tenement House Act required buildings housing the city’s working class to have outward-facing windows and other features that promoted ventilation.
There was another reason for the growing obsession with fresh air: the continuing threat of tuberculosis. Though it had declined somewhat by the turn of the century, the respiratory disease remained the third most common cause of death after heart disease and influenza.
Soon, a growing number of middle-class Americans embraced the idea that the only way to prevent it — and perhaps even cure it — was to spend as much time as possible outdoors. As medical historian Katherine Ott has observed, the fundamental point of what became known as the “rest cure” was, as one proponent put it, “to make our rooms indoors, as nearly as possible, parts of all outdoors.”
And they meant it. In the early 20th century, patients began sleeping with their bodies cantilevered on beds sticking out of windows. Many of those afflicted with tuberculosis left cities for sanitariums established in the territory of Arizona, land of sunshine and dry desert air.
But even the healthy embraced fresh air, spurring changes to domestic architecture. The idea of a “sleeping porch” — typically, a well-ventilated, screened area on the second floor where residents could spend the night — became de rigueur. So, too, did verandas and enormous porches designed to catch a breeze. The new “bungalow” style of architecture embodied many of these ideas.
In the 1920s, a group of engineers decided to tame nature — and encourage Americans to shut the windows.
The careers of these individuals — Alfred Wolff, Stuart Cramer and Willis Carrier — have been documented by historians of technology like Gail Cooper. It was Cramer, a textile engineer who worked in factories, who coined the phrase “air conditioning.” Significantly, this did not refer to cool temperatures so much as the idea that interior air could be maintained at constant levels of relative humidity in both winter and summer.
Cramer also took the fateful step of merging the mechanical systems that conditioned the air with those that ventilated his factories. This was understandable: It made little sense to regulate the humidity if the windows were wide open.
Willis Carrier took these ideas even further, and quickly became the face of air-conditioned spaces. He founded several companies that marketed air conditioning to factories, promising to “make every day a good day.” No longer would manufacturers need to worry about shifts in relative humidity that could ruin food processing and other operations.
Not everyone embraced the new technology. So-called open-air crusaders warned that no matter how sophisticated the machinery, there was simply no substitute for open windows for discouraging the spread of germs.
Ventilation engineers sought to allay these concerns by drafting codes that guaranteed an exchange of fresh air. But these inevitably collided with cost concerns: It was cheaper to recirculate indoor air than it was to pull it in from the outside.
The result was open conflict between the engineers and the crusaders. Long before “sick building syndrome” became a commonplace term, critics of climate control argued that mechanically processed air was less healthy and more dangerous during viral outbreaks.
The engineers won in the end, with air conditioning enjoying broad acceptance in the U.S. by the end of the World War II via two very different systems.The first was a dramatic expansion of the technology in workplaces — not just factories, but white-collar offices in skyscrapers and office parks. The second was the democratization of air conditioning in homes: window units at first, followed by large, central air conditioning systems.
Americans’ love of air conditioning fueled a dramatic shift of population to the Sun Belt. While the northeast only grew by 41 percent between 1940 and 1980, the region of the country below the 37th parallel grew by 112 percent — a trend that has only intensified in recent decades. But it was hardly restricted to that region, with the technology becoming commonplace in every state.
Today, the U.S. uses more energy for air conditioning than all other nations in the world put together, according to a Yale University study. In fact, between 1993 and 2005 alone, Americans doubled their energy consumption for air conditioning.
But climate control may have a downside, as our experience with the coronavirus suggests. Professor Edward Nardell of Harvard’s School of Public Health has argued that at first glance, summertime might deal a serious blow to a pathogen like COVID-19: Viruses don’t normally thrive in hot and humid weather.
But if everyone sits inside dry, climate-controlled environments sealed off from the outside, we’re more or less giving COVID-19 what it wants and needs to reproduce. Indeed, a growing number of scientists have argued that airborne transmission within climate-controlled spaces is a serious threat.
In the war against COVID-19, some of the most old-fashioned solutions have turned out to be the most effective. Wear a mask. Self-quarantine if you have symptoms. Push more activities outdoors. Should the simple act of opening windows be added to the list? It certainly won’t help beat the heat. But it might help beat the virus.
Stephen Mihm, an associate professor of history at the University of Georgia, is a contributor to Bloomberg Opinion.
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