Prolonged exposure to airborne asbestos particles increases the risk of several diseases:

Mesothelioma

Asbestosis - This disease develops after long-term heavy exposure to airborne asbestos fibers. This is a different situation from mesothelioma where a few months or even weeks of exposure may be enough to develop mesothelioma. Also, while Mesothelioma takes 20 to 50 years to develop, Asbestosis usually develops after 5 to 10 years to exposure to asbestos fibers. Unlike mesothelioma this disease is however non-cancerous. Asbestosis is the scarring of the parenchymal tissue of the lungs. Such scarring can occur when asbestos fibers reach the alveoli in the lungs. The severity of scarring depends on the degree of exposure to asbestos fibers. Individuals that suffer from asbestosis can develop conditions such as impaired breathing, which in rare circumstances may result even in respiratory failure. They have also a higher risk of developing mesothelioma and lung cancer. Asbestosis is a medical condition that lasts a lifetime and so there is not a definitive treatment for it. Shortness of breath can however be relieved by oxygen therapy. Other supportive treatments may include physiotherapy and the prescription of medications.

Pleural Disease - This disease may be an early sign for the development of other asbestos-related diseases. As in other asbestos related diseases, it develops because of heavy and prolonged exposure to asbestos fibers. Pleural disease is the scarring of the pleura (lining of the lungs). As the walls of the lungs become thickened, the body tries to remove the asbestos fibers. It often results in breathing difficulties.  

Lung Cancer - This cancer has a latency period (i.e. it develops) after twenty years or more after the exposure to airborne asbestos fibers. The risk of lung cancer increases greatly if the individual is also a smoker. The risk further increases if the individual is exposed to asbestos fibers and to cigarette smoking at the same time. 

Other Cancers -  These may include cancers of the kidney, gastrointestinal tract, larynx and oropharynx.

Tumors - These are benign tumors and so they do not spread to other parts of the body. Usually they pose little or no risk to the health of the individual.