[Chronic respiratory tract diseases--environmentally or occupationally-induced]

Chronic bronchitis, lung emphysema and bronchial asthma are the most frequently encountered pneumological diseases. Most patients with chronic bronchitis and emphysema are smokers, therefore the development of the disease is closely related to self responsible habits. In asthmatics bronchial hyperresponsiveness favours a pathologic airway response induced by polluted air. SO2 is believed to only induce airway obstruction in patients with preexisting airway diseases. NO2 and ozone, however, have been shown to induce airway hyperresponsiveness in healthy subjects.