In order to study the effect of air pollution on the ventilatory function of lung, pulmonary function studies were carried out in middle school students (male) living isn Sasang industrial area more than 10 years, and were compared with those of control group. The following results were obtained; 1. Lung capacities were normal in observed & control group, and were not significantly different between two groups. 2. The respective parameters of ventilatory function test of observed group were smaller than that of control group, but FVC, $FEV_1$, $FEV_1/FVC$, FEF 25-75%, Vmax 50, MVV of two groups were normal. 3. PEFR, Vmax 25, Vmax 75 of observed group were significantly decreased, and there were statistically significant differences between two groups in FEF 25-75% (p < 0.01), Vmax 25 (p < 0.05), Vmax 50 (p < 0.01), Vmax 75 (p < 0.05), PEFR (p < 0.05) and MVV (p < 0.02).