I worked with a group whose office was basically a big supply area converted into an office to hold around 7 cubicles. Zero windows, and while I am sure the HVAC system cycled in fresh air, I doubt it was enough because by lunch time I was ready to fall asleep whenever I worked in there.

Biggest perk of working from home was having control over my environment. Because of that, I think I feel the best I have in years.