• Go into a room where the shutters are always shut (in a sick-room or a bed-room there should never be shutters shut), and though the room be uninhabited-though the air has never been polluted by the breathing of human beings, you will observe a close, musty smell of corrupt air-of air unpurified by the effect of the sun's rays.

    Florence Nightingale (1876). “Notes on Nursing for the labouring classes. With a chapter on Children”, p.68