This piece by @zeynep explaining the significance of the CDC and WHO announcing that the coronavirus is airborne--and why it took so long to get here--is really great. I want to add a few things about the historical change, and the history of urban public health. #histmed https://twitter.com/zeynep/status/1390738628528201735

As I wrote in @madebyhistory a few weeks ago, health prevention does not need to be either/or--either fighting aerial transmission or fighting contact transmission, but that is the culture built up over the last 100-150 years. https://www.washingtonpost.com/outlook/2021/04/21/revisiting-19th-century-medical-idea-could-help-address-covid-19/

However, the knowledge that diseases spread more readily in (over)crowded spaces and the late #C19 enthusiasm for ventilation did not translate into better ventilation practices. Where public health met urban governance and private property, it met resistance.

The Tenement Acts in New York State are such a clear example of this problem. See my and @KaraSchlichting's open access article for how invisible inequalities of fresh air and temperatures were KNOWINGLY built into the urban environment. https://vtechworks.lib.vt.edu/bitstream/handle/10919/101613/j.jhes.5.122472.pdf?sequence=1&isAllowed=y

Through the Tenement Acts, health reformers and legislators tried to require ventilation and other necessary sanitary provisions in NYC apartments (ie tenements), but builders and landowners worked around that goal via James Ware's design for dumbell tenements.

These buildings maximized the building space on NYC's narrow lots and provided windows--but not the ventilation these windows were meant to provide. When dumbbells were built side by side, windows opened on air shafts rather than fresh air.

While I appreciate @zeynep's optimism for how different public health would be if airborne transmission had been accepted sooner, changing the environment in healthful ways requires as much (prob. more) political will than scientific knowledge. The two have rarely moved in step.

Last thing for now--my use of environment is deliberate. ALL of our spaces--workplaces, homes, parks--are built environment and the structures that have or haven't been built into them. Our renewed focus on the air reminds us that the environment is a huge factor in health.