My guess is that a large part of the difference in indoor environments would be humidity + CO2 levels. Florida buildings are designed for a lot more airflow and have more attention paid to up-front HVAC design, so there's less "sick building syndrome" type stuff going on.
In a Florida summer, the outdoors is a swamp, but you don't have to spend much time there. The whole place is built for cars; you can (if you wish) go straight from building A, to your car, to building B. Presuming underground parking, you might never even touch non-air-conditioned air.
In an NYC summer, meanwhile, in many buildings, the indoors is the swamp. (And often their attached yards / alleyways as well, if they're enclosed around by tall buildings.)
In a Florida summer, the outdoors is a swamp, but you don't have to spend much time there. The whole place is built for cars; you can (if you wish) go straight from building A, to your car, to building B. Presuming underground parking, you might never even touch non-air-conditioned air.
In an NYC summer, meanwhile, in many buildings, the indoors is the swamp. (And often their attached yards / alleyways as well, if they're enclosed around by tall buildings.)