I don't know how working people survived without air conditioning,
Many larger buildings had (what was then considered to be) air conditioning. Skyscrapers prior to the "sealed glass box" era were designed with vertical air shafts running the entire height of the building. On each floor or pair of floors, an air-handler would pull air out of the shaft into each floor through a system of ventilation ducts; it would be exhausted through the windows.
I've been in one of the vent shafts at the Empire State Building, and I've seen the top of one at Boston's Prudential Tower. After central air was installed at Empire, the vent shafts gained a new purpose as communications corridors, particularly connecting the broadcast facilities on the 79th, 80th, 81st, 84th, and 85th floors.
-GAWollman