Infectious disease lessons for today from New York City tenement reform 

In March 2022, President Biden announced the Clean Air in Buildings Challenge designed to lessen the risk of airborne infectious disease transmission in buildings, schools, and homes. Since the announcement, public health experts and engineers have created ventilation and filtration standards to meet the challenge. Updating buildings to these modern standards and pairing them with a serious commitment from federal and local governments to ensure improvement, compliance, and funding can kickstart a new clean air movement today. In the process, we can build safer homes, schools, and workplaces, create a healthier population and workforce, and increase housing stock to make cities and towns more affordable, allowing the benefits of clean air reforms to multiply. To see this, we can look to history — the New York City tenement acts of the 19th and early 20th century created similar initiatives and benefits.  

Throughout the 19th century, epidemic disease was part and parcel of New York City life. An average of about one out of every 100 Manhattan residents died yearly between 1868 and 1910 from outbreaks of cholera, measles, smallpox, yellow fever, and other infectious diseases. Many city residents blamed the dense and dirty tenement neighborhoods, such as Five Points, for these outbreaks. 

In the early 19th century, the city filled the formerly bucolic Collect Pond when it became too polluted from nearby tanneries, breweries, and factories. Developers built a new neighborhood atop the former pond and named it Paradise Square. However, the neighborhood was anything but paradise. Buildings sank in the wet and marshy land. Streets were continually soiled and muddy. 

As conditions deteriorated, the wealthy moved out. Developers subdivided former factories, warehouses, and apartment buildings into a maze of makeshift residences—many containing just a single room—to house impoverished new immigrants who replaced the wealthy. The area became known as Five Points and grew a reputation as the most notorious tenement neighborhood in New York City.

Most apartments in Five Points and other early tenement neighborhoods lacked sanitation. Some were devoid of windows and light. In the wet conditions, basements and streets infested with bacteria from the unsanitary disposal of human waste carried diseases like cholera into homes. Unventilated, windowless apartments trapped airborne diseases like tuberculosis and measles within. In these conditions, morbidity and mortality flowed throughout the poorest tenements.  

To improve safety the city passed a series of “tenement acts” beginning in 1867. These laws mandated improved sanitation and ventilation in newly erected buildings. Surprising to many, some tenement neighborhoods became as safe as wealthy neighborhoods while others continued to match the stereotype of epidemic “hot-beds.” For the most part, the Lower East Side (LES) tenements, home to many Jewish and German immigrants, had infectious disease mortality around 20 percent lower than the city-wide average. Other central and western tenement neighborhoods in southern Manhattan, such as the 6th Ward (containing Five Points), continued to exhibit high rates of infectious disease mortality about 25 percent higher than the city-wide average.

Why did some tenement neighborhoods become safe and others did not? Data show that these differences did not occur because of common measures like population density, average wealth, or environmental factors. Instead the LES became safer from infectious disease due to its being one of the fastest growing neighborhoods in the city. This growth caused the continual building of new tenements that were in compliance with the safer ventilation and sanitation requirements of the tenement acts. The Report of The Tenement House Department of the City of New York 1902/1903 lists that 45 percent of all new apartment buildings in Manhattan were constructed in the LES. These new buildings were safer. 

Other tenement neighborhoods had less new construction. Many of their older buildings lacked ventilation shafts, courtyards, windows opening to a source of fresh air, and other safety measures required in newly constructed buildings. As such, their residents continued to suffer from infectious disease in these older ramshackle, poorly ventilated, and unsanitary buildings. 

Ironically many 19th century New Yorkers viewed immigrants as the bane of urban health. Yet, the population growth they provided gave the city an opportunity. Older, less dense housing was torn down in order to accommodate immigration. The compliant new housing propelled New York City to a safer future for everyone. 

Today, as the most devastating infectious disease crisis in over a century continues, we need reform again. Many contemporary buildings keep us cool in summer and warm in winter by limiting the exchange of air with the outside world. Yet, even in this sealed environment, technology can keep the air safe with modern filtration systems, air purifiers, and germ-killing UV light. It is time to require these improvements widely across society to unlock their array of benefits, not the least of which is a healthier population. The cost to the economy of large epidemic outbreaks can be enormous. There are ethical considerations as well because the largest health and economic costs of infectious disease outbreaks often fall on the least privileged.  

In the 19th century much of humanity cleaned its water and nearly eliminated many devastating water-borne diseases such as cholera. The tenement acts in New York City initiated a clean air movement that improved society but eventually stalled. It is time to remember these lessons and couple them with 21st century technology to ensure that tomorrow’s air is as safe as our water. 

Jason M. Barr is a professor of Economics at Rutgers University-Newark. He writes the Skynomics Blog and his latest book, “Cities in the Sky: The Quest to Build the World’s Tallest Skyscrapers,” will be published by Scribner Books in May 2024. Troy Tassier is a professor of economics at Fordham University and the author of “The Rich Flee and the Poor Take the Bus: How Our Unequal Society Fails Us during Outbreaks” and the substack newsletter, At the Margin.