Disorders of the respiratory system

Asthma: difficulty in breathing with wheezing, caused by inflammation of the bronchi and bronchioles.

Emphysema: a chronic disorder that damages the alveolar walls, so less respiratory surface is left for gas exchange. One of its major causes is cigarette smoking.

Occupational respiratory disorders: work such as grinding or stone-breaking throws up more dust than the body's defence mechanisms can fully deal with.

Long exposure to such dust causes inflammation that leads to fibrosis, a proliferation of fibrous tissue, which causes serious lung damage.

Workers in these industries should wear protective masks.