[Health significance of inhaled particles]

Particulates refer to particles, dust, dirt, soot and aerosol mists that has suspended in the surrounding air. They may consist of solids of various forms including fibres or liquids. Long term exposure to silicon dioxide containing dusts (crystalline silica: quartz, tridymite, cristobalite, coesite, stishovite) may cause pneumoconiosis in the form of acute or/either chronic silicosis. Asbestos refers to a divers family of crystalline hydrated fibrous siliates typically exhibiting a greater tha 3:1 length ot diameter ratio. It is subdivided into serpentine (Chrysotile) and amphibole (crocidolite, amosite, anthophyllite, tremolite, actinolite). Exposure to asbestos fibres may cause lung fibrosis and promote cancer of the lung or the pleura. Besides the induction of malignant diseases dust exposure may result in obstructive as well as restrictive lung diseases which may be compensate in case of the recognition as a occupational diseases. Other occupational exposures leading to pneumoconiosis are caused be talc, or metals including aluminium containing dusts. Also the group of man-made mineral (MMMFs) or vitreous fibres (MMVFs), including glass wool, rock wool, slag wool, glass filaments, microfibres, refractory ceramic fibres are bioactive under certain experimental conditions. Although it has been shown that MMMFs may cause malignancies when injected intraperitoneally in high quantities in rodents, inhalation trials and human studies could not reproduce these results in the same precision. Fine particles (particulate matter = PM) comprise one of the most widespread and harmful air pollutants in the industrialized world. PM may cause worsening of asthma and other respiratory diseases, reduce lung function development in children, potentially increased the risk of premature death in the elderly and enhance mortality from cardiac diseases. Because of the small size PM2.5 is seen to be even more hazardous than PM10.