Hospital wards can be polluted o made dirty by bacteria in droplet infections–dangerous germs being those causing tuberculosis, sore throats, meningitis, and influenza.
There are two types of ventilation: natural and mechanical ventilation.
1. Natural Ventilation
This takes place when air blows in through the windows, or when a wind blows across a chimney and sucks out warmed air. It may take place when heat from a fire or a crowd of people warms the air around it; the air raises and colder air flows in to take its place. This is called convection. The warmed air then escapes through a chimney or ventilator.
Aids to natural ventilation are ventilators, louvred panes, fans, perforated bricks, and gratings.
2. Mechanical Ventilation
Fans and air-conditioning units are used in buildings where there is enough money to pay for them.
There are local regulations about ventilation contained in the Public Health Laws which apply to buildings in towns, townships, planning areas, trading centers and factories. These state all buildings should have cross-ventilation, and in a public building there must be certain measurements in area of window per area of floor space.
Living in poorly ventilated rooms produces an increased rate of cross-infections with respiratory.