Evidence for ozone-induced small-airway dysfunction: lack of menstrual-cycle and gender effects

Am J Respir Crit Care Med. 1995 Sep;152(3):988-96. doi: 10.1164/ajrccm.152.3.7663815.


Recently, we analyzed FEF25-75 isovolumetrically to assess the acute effects of ozone (O3) on small-airway function: the reduction in isovolumetric (isoV) FEF25-75 at end exposure progressed during the next 25 min even as FVC was recovering. To evaluate this effect over a longer period, we measured isovolumetric FEFs, helium-oxygen (He-O2) volume of isoflow (VisoV), the multiple breath nitrogen washout (MBNW) curve, FRC, and RV in 24 subjects 24 h after a 130-min exposure to filtered air (FA) and O3 (0.35 ppm). Men and women were studied to test for gender-based differences in response, after first determining that menstrual-cycle phase did not itself influence response. Isovolumetric FEF25-75, Vmax50, and Vmax75 were reduced about equally at 25 min after O3 exposure (p < or = 0.02) and showed no recovery at 24 h. FVC and FEV1, although still depressed after 24 h (p < 0.05), showed substantial recovery (p < 0.01). FRC, RV, and VisoV showed no effect of O3 exposure. No gender differences in O3 responsiveness were found. In summary, O3-induced reductions in isovolumetric flow rates, suggestive of small-airway dysfunction, may persist for 24 h following acute exposure to O3, a time-course consistent with inflammation.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Bronchi / drug effects*
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Menstrual Cycle / physiology*
  • Ozone / adverse effects*
  • Respiratory Function Tests
  • Respiratory Mechanics / drug effects*
  • Sex Factors
  • Vital Capacity


  • Ozone