Snow couldn’t know it at the time, but he had created the modern discipline of public health — attacking the diseases that afflict large numbers of people rather than ministering to individuals one at a time.
In the years since then, public health has accomplished a great many remarkable things, some of which we appreciate and some of which we don’t. The mid-20th century was its period of greatest glory. In 1943, public health physicians discovered streptomycin, an antibiotic that was effective against tuberculosis, perhaps the most feared and tragic urban disease of the previous century, and within a decade tuberculosis was curable for virtually everyone who contracted it.
Most dramatic for my generation, of course, was the Salk polio vaccine, developed in the early 1950s. It transformed an era from one in which millions of parents were terrified to expose their children to the risks of contact at parks, beaches and playgrounds to one that rendered all these forms of recreation safe. This was the greatest of the many public health miracles of the century.
In the past year or so, we have witnessed another public health miracle. Within a year of COVID-19’s first appearance, and against the conventional wisdom of most predictions, scientists perfected vaccines that saved hundreds of thousands of American lives in a comparatively short time. The difference between this discovery and the previous ones is that few of us realize just what an achievement it was, and a significant minority of Americans refuse to be vaccinated at all. This is something entirely new. Virtually no one refused the polio vaccine when they had a chance to get it. When it comes to public health, we are living in a dramatically different world.
THE QUESTION OF THE MOMENT is what the profession of public health can do to renew itself. It can launch massive education campaigns to persuade the reluctant that vaccines are safe. But it is already doing that, with only sporadic success. Or it can expand to whole new fields of endeavor. That is what Dr. Richard Jackson, the public health scholar and former environmental health director of the Centers for Disease Control and Prevention, is trying to do. He argues that public health bears a crucial connection to the built environment and the design of cities. Between 30 percent and 45 percent of carbon emissions, according to Jackson, are consequences of the built environment.
“Health was not in consideration when we were making these decisions,” Jackson told me in a recent conversation. “The blind spot that we have is human well-being.”
It might be argued that the modern campaign for public health through design got its effective start with the heat wave tragedy in Chicago in 1995, when the temperature reached 106 degrees and at least 739 people reportedly lost their lives because the slum apartment buildings they were living in had been poorly constructed or maintained. Flat roofs retained heat rather than dispersing it. Windows were locked, many for fear of crime, making fresh air an unattainable commodity. As Jackson says, “What we were doing to our environment was making it hotter.”
A fair amount of public health by design has to do with re-engineering temperature, especially making the environment cooler in abnormally hot times and places. Reducing the amount of blacktop pavement is one way to do this; too much blacktop creates a heat trap. Protecting tree cover is one more; ample tree cover has been shown to reduce the prevalence of asthma in large cities.
Some of the things the public health/design movement recommends are fairly obvious; some are not. There are still people who dispute that excess body weight is a critical health problem for Americans; there is virtually no one who doubts that regular exercise makes people of all ages healthier. There are lots of ways we could address this issue, but one important one involves finding ways to induce children to walk to school instead of riding in cars. In 1969, 48 percent of schoolchildren walked or biked to school. By 2009 that number had declined to 13 percent.
![John Snow](https://erepublic.brightspotcdn.com/dims4/default/efa836f/2147483647/strip/true/crop/250x358+0+0/resize/840x1203!/quality/90/?url=http%3A%2F%2Ferepublic-brightspot.s3.us-west-2.amazonaws.com%2F35%2Fcc%2Fad0b66e749eb97a48dae39fd9c1e%2Fehrenhalt-public-health-snow.jpg)
A part of that can perhaps be attributed to creeping laziness, but more of it has to do with the location of schools in outlying areas and the near-total absence of sidewalks connecting schools with residential developments. More sidewalks and paths and less-threatening streets would create more walkers, environmental design researchers insist, and those design improvements would give us healthier kids.
It isn’t just sidewalks to school that make up a fundamental tenet of design for health — it’s crosswalks, especially in poorer suburbs with large numbers of residents who don’t own cars. If you are a carless grocery shopper in a lower-class suburb, you may have to walk a mile or more to pick up your groceries, then another mile or more to get home, mostly because there is no safe place to cross the street. You will be sorely tempted to make a dangerous mid-block crossing, and those poor decisions are a significant part of the reason why pedestrian deaths in America, instead of declining with fewer auto miles driven, are actually increasing.
Stairways are as much a focus of this movement as sidewalks. Numerous studies have shown that in office buildings with wide and attractive staircases, workers will walk upstairs, doing their bodies a long-term favor. Making stairways more enticing may include adding windows that give them access to daylight; some researchers believe that if the World Trade Center had had more open and less-intimidating stairways, more tenants of the building would have used them and saved their lives.
Some design-for-public-health advocates also talk about the need to recognize a societal “right to breathe,” which would mandate better ventilation in crowded facilities, especially prisons, nursing homes and cruise ships, all of which generate disturbingly high rates of asthma. Adding air filters to newly built private residences would help to deal with this problem as well.
WHEN IT COMES TO THE LARGER BUILT ENVIRONMENT, design-for-health ideas can require significant buy-in from architects, developers and public officials. One of them, a key tenet of the New Urbanism movement, is the desirability of designing new suburban projects around open plazas rather than arterial roads and cul-de-sacs. Plazas are desirable not only as healthy open-air spaces but as magnets for the casual sociability that seems to be connected with better mental health.
This is one of the relatively few design-for-health recommendations that seems to have gained ground in the past decade. Plazas are fitting into an increasing number of suburban developments and are part of the strategy used as a marketing tool for developers who aim to lure young families out of more-stressful urban neighborhoods without forcing on them the car-dominated suburban sprawl they are eager to avoid. The expansion of outdoor dining in the last couple of years is a modest victory; it was almost entirely a product of the coronavirus, but there is no reason to believe it will go away once COVID-19 subsides.
I’m in agreement with the bulk of the ideas this movement is promoting, although I do have a quibble or two. Jackson would impose on developers, in addition to environmental impact statements for their projects, health impact statements that would outline the public health consequences of the buildings and landscapes they propose to create. At the same time, design-for-health advocates complain about the bureaucratic red tape that is making it difficult to produce the new affordable housing the nation badly needs. Adding health impact studies, in addition to forcing predictions that are difficult to make in the long run, would add significantly to the red-tape problem. I’m not sure the gain would be worth the loss.
All in all, though, we are dealing with ideas that not only make sense, but harken back, perhaps surprisingly, to the very beginning of the public health profession in the 19th century. When the American Public Health Association was founded in 1872, a substantial number of its charter members and allies were designers and urban planners, including the legendary landscape architect Frederick Law Olmsted, who saw creations such as his own Central Park in New York to be sources of human health and well-being in addition to objects of beauty. Those original public health advocates knew quite a few things that we seem to have forgotten in the 150 years since. If we can do a better job of remembering them, we will at long last be on the right track.
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