[Heterogeneity of lung ventilation as an indicator of early occupational exposure effects on the respiratory system].

The homogeneity of lung ventilation was evaluated in 148 male workers without any evident symptoms of impaired lung ventilation who were employed as miners (94 persons) and processors (52 persons) of PbS ore. The V2:V1 factor was calculated from the resultant of the maximum flow and volume. In the group of miners, significant increase of homogeneity was found to occur in elder workers (over 35 years of age) and in those employed for a longer period of time (above 10 years). Ventilation heterogeneity in that group was also intensified by simultaneous occurrence of chronic bronchitis. In the group of the floatation plant workers, there was a similar relationship between the ventilation heterogeneity and their age as well as employment period. As no effect of tobacco smoking on the discussed parameter was detected, it can be presumed that the effect of the working environment factors was predominant.