A few years ago, when I still had confidence in our modern ability to fight viruses, I pored over a photo essay of the 1918 flu pandemic. How quaint, I remember thinking, as I looked at people bundled up for outdoor classes and court and church. How primitive their technology, those nurses in gauze masks. How little did I know.
I felt secure, foolishly, in our 100 additional years of innovation. But it would soon become clear that our full-body hazmat suits and negative-pressure rooms and HEPA filters mattered little to Americans who couldn’t find N95 masks. In our quest for perfect solutions, we’d forgotten an extremely obvious and simple one: fresh air. A colleague joked, at one point, that things would have gone better in the pandemic if we still believed in miasma theory.
Miasma theory—discredited, of course, by the rise of germ theory—held that disease came from “bad air” emanating from decomposing matter and filth. This idea peaked in the 19th century, when doctors, architects, and one particularly influential nurse, Florence Nightingale, became fixated on ventilation’s importance for health. It manifested in the physical layout of buildings: windows, many of them, but also towers erected for the sole purpose of ventilation and elaborate ductwork to move contaminated air outdoors. Historic buildings still bear the vestigial mark of these public-health strategies, long after the scientific thinking has moved on.