Respiratory epithelium exposed to sulfur dioxide--functional and ultrastructural alterations.

The value of morphological investigations of airway mucosa should be compared to a functional method when estimating the toxicity of airborne pollutants. In 34 guinea pig tracheas, mucociliary activity was measured using a modified light beam reflex method before and following exposure to sulfur dioxide for 30 minutes in concentrations ranging between 7.5 and 37.5 mg/m3. Exposure to air served as a control. Simultaneously, specimens were taken for light and electron microscopy. Mucociliary activity decreased from 8.4 +/- 2.9 Hz (control exposure) to 4.0 +/- 2.9 Hz following exposure to 7.5 mg/m3, to 3.4 +/- 2.7 Hz at 15 mg/m3 sulfur dioxide, to 1.8 +/- 2.2 Hz at 22.5 mg/m3 sulfur dioxide, t…