“…In the latter view, deformation of MEFV curves reflects alteration in periph eral airways caliber, phase III slope devia tions represent abnormalities in the elastic properties of the air spaces, and a rise in closing volume can result from both periph eral airway disease and loss of elasticity. Use of single-breath nitrogen and MEFV curves obtained in concert has been infor mative in longitudinal studies of the effects on pulmonary target areas of subjects ex posed to direct [39] and indirect [4] inhal ants, and may detect changes from environ mental pollutants over and above cigarette effects [34], There have been no similar prospective studies of the pulmonary re sponses of healthy subjects to hair-grooming aerosols, the relationship between their use and lung abnormalities resting on the in ferences of animal studies [20], radiologic correlations [25] and occupational investi gations [33,37]. With the exception of the notable Zuskin and Bouhuys contribution [40], the few respiratory function analyses of nonoccupational effects of hair-sprays used the less sensitive spirometric methods [18, 281. Our results in the initial phase of a pro spective study do not confirm the ability of the hair-spray aerosol used to induce acute changes in the small airways of healthy subjects, even with exposures exceeding the manufacturer's instructions for 'heavy' ap plication.…”