The association between short term changes in ambient air concentrations of TSP and SO2 and day to day fluctuations in mortality was analyzed in the highly polluted Northern Bohemia region inhabited by approximately 630 000 people. A logistic regression model was adjusted for long term trends, seasonal cycles, influenza epidemics and weather parameters. The pollution and mortality data were available from 1982 to 1994. When the association was evaluated regardless of gender and age, 100 mg/m 3 increase of TSP, but not SO2, was associated with a 3.4 % increase of daily mortality lagged by 2 days. Evident differences in this association have been found between men and women. A significant increase in daily total and CVD mortality was observed in men below 65 while in women of the same age we found no association or even significant decrease in daily mortality. For the population over 65 the differences between genders were again apparent. The mortality in women increased significantly while in men significant decrease was demonstrated. Conclusions: The evaluation with respect to gender might contribute to identifying susceptible subgroups.

        Key words: air pollution, daily mortality, gender differences.