Background: Pulmonary function impairments are likely to result from acute exposure to excessive ambient air particulate matter (PM) and noxious gases.

Aim: To investigate the effect of acute exposure of ambient air pollution on spirometry parameters and respiratory impedance.

Methods: Recruitment of healthy subjects (n=19, 12 males) was done with age of 25±7.39 yrs at two different time points; when air quality index was less than 150 for 7 consecutive days and when it was more than 300 for 7 consecutive days. Measurement of lung volumes and capacities was done by spirometry and respiratory impedance consisting of resistance and reactance was estimated by impulse oscillometry at both time points.

Results: Even though spirometry and impulse oscillometry parameters were in normal range, significantly lower forced vital capacity (% pred.) (85.65±10.74 Vs 90.81±10.25; p=0.046), forced expiratory volume at 1st second (% pred.)  (79.18±13.82 Vs 89.89±8.40; p=0.0002) and peak expiratory flow (% pred.)  (72.06±23.90 Vs 81.46±20.40; p=0.034) were observed during the high pollution as compared with low pollution time point. Significantly higher total airway resistance - R5 (% pred.) (103.9[99.04-112.9] Vs 75[69.23-88.46]; p=0.0015), central airway resistance- R20%predicted (111.2[100-122] Vs 81.82[72.73-92.86]; p=0.0002) and lower airway reactance X5 (-0.11[-0.17-(-0.09)] Vs -0.07[-.1-(-0.06)]; p value= 0.001) were observed during the high pollution as compared with low pollution time point.

Conclusion: Acute exposure to air pollutants significantly affects spirometry parameters and respiratory impedance in healthy subjects