Bacteria and viruses from patients themselves. Disinfectants and steriliants. Laser and electrocautery plume. In some instances, periodic sampling of airborne particles will help to verify filter placement and air quality control. In addition, factors such as construction management and planning can prevent costly litigation in the long run.
Small matters count.
For example, vacuum cleaners which are poorly maintained may be the source of infectious particles in patient wards. It is this type of awareness and action which will help to minimize environmental risks to the occupants of hospitals and healthcare facilities.