SO2 (35S LABELED) ABSORPTION BY NOSE AND MOUTHUNDER CONDITIONS OF VARYING CONCENTRATION AND FLOW

Sulfur dioxide35S (35SO2) was administered to the surgically isolated upper airways of anesthetized dogs via a mask with separate connections to the nose and mouth. The 35SO2 that passed through the upper airways was monitored continuously; nearly complete removal could be measured to within several hundredths of a percent. Nasal uptake of the incoming gas (1 to 50 ppm) exceeded 99% at a flow of 3.5 liters/min and fell only several percent when flow was increased tenfold (1, 10 ppm). Uptake by the mouth averaged more than 95% at a flow of 3.5 liters/min (1, 10 ppm) but fell to under 50% when flow was increased tenfold. Following penetration of the mouth or nose by 35SO2, desorption of the gas from the mucosa could be demonstrated more than 25 minutes after the end of exposure. © 1969 Taylor & Francis Group, LLC.