Air-conditioning systems are designed to control air temperature and humidity, air exchange and to filter dust and other particles.|
The simplicity of the technical solutions must be compatible with a controlled and lasting management.
In practice, in many cases the air-conditioning system does not carry out its functions properly and furthermore it carries or becomes a source of noise, vibrations, microbiological polluting agents, dust and gases.
Micro-organisms may proliferate in many parts of the air-conditioning system and may cause epidemics or isolated cases of legionnair's disease and extrinsic allergic alveolitis by actynomycete thermophile; probably even the so called "monday or humidifiers' fever", characterized by glandular fever-like illness that arises on the first working day of the week, is a hypersensitivity pneumonia caused by the diffusion, through the rekindled system, of microorganisms that had been proliferating during the week-end.
The most typical pathology linked to air quality is the Sick Building Syndrome. This is characterized by eye disorders and by troubles of the upper airways (ocular and pharyngeal dryness, nasal stenosis or rhinorrhea, aspecific reactivity of these mucous membranes), skin disorders (dryness, irritation), nervous disorders (drowsiness, headache), sensorial problems (special senses disorders). Symptoms are usually light and appear at least weekly; they improve with rest from work. Many investigations have pointed out that this syndrome is more frequently found in offices located in modern buildings equipped with air-conditioning systems, rather than in traditional buildings with natural ventilation. The pathogenesis of the disorders is not clear, even though in the majority of cases it is necessary to exclude allergic phenomena.