A mass screening of lung function associated with air pollutants for children is limited. This study assessed the association between air pollutants exposure and the lung function of junior high school students in a mass screening program in Taipei city, Taiwan. Among 10,396 students with completed asthma screening questionnaires and anthropometric measures, 2919 students aged 12-16 received the spirometry test. Forced vital capacity (FVC) and forced expiratory flow in 1s (FEV(1)) in association with daily ambient concentrations of particulate matter with diameter of 10 μm or less (PM(10)), sulfur dioxide (SO(2)), carbon monoxide (CO), nitrogen dioxide (NO(2)), and ozone (O(3)) were assessed by regression models controlling for the age, gender, height, weight, student living districts, rainfall and temperature. FVC, had a significant negative association with short-term exposure to O(3) and PM(10) measured on the day of spirometry testing. FVC values also were reversely associated with means of SO(2), O(3), NO(2), PM(10) and CO exposed 1 d earlier. An increase of 1-ppm CO was associated with the reduction in FVC for 69.8 mL (95% CI: -115, -24.4 mL) or in FEV(1) for 73.7 mL (95% CI: -118, -29.7 mL). An increase in SO(2) for 1 ppb was associated with the reductions in FVC and FEV(1) for 12.9 mL (95% CI: -20.7, -5.09 mL) and 11.7 mL (95% CI: -19.3, -4.16 mL), respectively. In conclusion, the short-term exposure to O(3) and PM(10) was associated with reducing FVC and FEV(1). CO and SO(2) exposure had a strong 1-d lag effect on FVC and FEV(1).