Concentration-dependent respiratory response of guinea pigs to a single exposure of cotton dust.

Eight groups of guinea pigs were exposed to cotton dust at concentrations of 2 to 27 mg/m3. Each exposure was for 6 hr. The pulmonary function of each animal was assessed prior to exposure, following exposure, and 18 hr following exposure. Tidal volume decreased while respiratory frequency increased in a concentration-dependent manner. These changes were amplified when the same measurements were conducted while the animals were breathing an atmosphere containing 10% CO2 in 19% O2 and 71% N2. Greatest response was noted at 18 hr postexposure. The concentration-response effects can be applied to evaluate the respiratory potencies of different cotton dusts grown under a variety of conditions.