Reversible fraction of airway resistance in healthy children of areas with different levels of atmospheric pollutants.

Reversible fraction of airway resistance (delta Raw) has been defined as the difference between airway resistances (Raw) before and after inhalative treatment with ipratropium-bromide (Atrovent) aerosols in healthy subjects. We examined delta Raw in children between 6-8 years of age living in areas with different air qualities. We found small but statistically significant (p less than 0.1) greater delta Raw for children of higher polluted areas. This could indicate that children of polluted areas possessed higher bronchial smooth muscle tone.