Most hospital rooms I've seen have sealed windows that can't be opened. This seems quite depressing. It's 
sad enough that patients are bedridden in a foreign and frightening place; in temperate seasons, must they also be deprived of fresh air and birdsong? But I always assumed this to be a necessary cost of efficient, hygienic ventilation.
That, however, may not be the case. In a study of eight Peruvian hospitals, UK researchers found that open windows and doors circulate more air than mechanical ventilation systems.
Because air isn't recirculated, the researchers suggest that naturally ventilated rooms are also less likely to spread airborne disease (a suggestion with which any victim of multiple airplane colds is likely to agree). And though the authors don't extrapolate their findings to the non-hospital world, it seems a logical jump.
Pay attention, architects!
Opening windows may be the best way of preventing transmission of airborne infection [Press Release]
