at lower o3 concentrations , responses were diminished in magnitude , and in rats exposed to 0.2 ppm o3 , only mo2 was significantly decreased , irritant-induced depression of ve did not imply a state of hypoventilation or hypoxia because ventilation equivalent for o2 ( ve/mo2 ) did not decline during o3 exposures .
C0030054
o2
C0030106
o3