One explanation for this phenomenon is that the initial rapid proliferation of 'modern' radiators in NYC happened around the same time as the 1918 influenza pan

One explanation for this phenomenon is that the initial rapid proliferation of 'modern' radiators in NYC happened around the same time as the 1918 influenza pandemic. It was understood that fresh air was something of an antidote. Tangentially, people wore masks as well during that global pandemic [1] and there were even anti-mask groups. [2] It makes me wonder what a pandemic a hundred years from now would be like and what physical manifestations of 2020 will remain. [1]: https://twitter.com/georgiatech/status/1307410628470956032 https://twitter.com/georgiatech/status/1307410628470956032 [2]: https://en.wikipedia.org/wiki/Anti-Mask_League_of_San_Francisco https://en.wikipedia.org/wiki/Anti-Mask_League_of_San_Franci...