Acute effect of sulphur dioxide from a power plant on pulmonary function of children, Thailand

Background Epidemiological studies have shown reversible declines of lung function in response to air pollution, but research on the independent effect of short-term exposure to ambient sulphur dioxide (SO2) on pulmonary function is limited. This study evaluated the association of short-term exposure to increased ambient SO2 and daily pulmonary function changes among children with and without asthma. Methods The associations of daily exposure to SO2 and particulate matter 10 mum in diameter (PM10) with pulmonary function were examined in 175 asthmatic and non-asthmatic children aged 6-14 years who resided near a coal-fired power plant in Thailand. Each child performed daily pulmonary function tests during the 61-day study period. General linear mixed models were used to estimate the association of air pollution and pulmonary function controlling for time, temperature, co-pollutants, and autocorrelation. Results In the asthmatic children, a daily increase in SO2 was associated with negligible declines in pulmonary function, but a small negative association was found between PM10 and pulmonary function. A 10-mug/m(3) increment was associated with changes in the highest forced vital capacity (FVC) (-6.3 ml, 95% CI: -9.8, -2.8), forced expiratory volume at 1 second (FEV1) (-6.0 ml, 95% CI: -9.2, 2.7), peak expiratory flow rate (PEFR) (-18.9 ml.sec(-1), 95% CI: -28.5, -9.3) and forced expiratory flow 25 to 75% of the FVC (FEF25-75%) (-3.7 ml.sec(-1), 95% CI: -10.9, 3.5). No consistent associations between air pollution and pulmonary function were found for non-asthmatic children. Conclusion Declines in pulmonary function among asthmatic children were associated with increases in particulate air pollution, rather than with increases in SO2.