A Panel Study on Lung Function and Bronchial Inflammation among Children Exposed to Ambient SO2 from an Oil Refinery

Abstract

To determine the acute effects on respiratory function of children exposed to sulphur dioxide (SO2), we conducted two population-based longitudinal investigations near a major oil refinery. We enrolled 233 children, age 8–14, in Sarroch (Italy). The first study entailed five monthly spirometric visits (Panel 5). In a subgroup, children positive for history of respiratory symptoms were tested weekly (20 times) with spirometry and fractional exhaled nitric oxide (FeNO) measurement (Panel 20). Baseline questionnaires and daily diaries were recorded. SO2, NO2, PM10 and O3 were measured by monitoring stations. Multiple regression models were fitted. Using a multipollutant model, we found that a 10 µg/m3 SO2 increase at lag0–2 days determined a percent variation (PV) of −3.37 (90% confidence interval, CI: −5.39; −1.30) for forced expiratory volume after one second (FEV1) in Panel 5 and a PV = −3.51 (90% CI: −4.77; −2.23) in Panel 20. We found a strong dose-response relation: 1-h SO2 peaks >200 µg/m3 at lag2 days = FEV1 PV −2.49. For FeNO, we found a PV = 38.12 (90% CI: 12.88; 69.01) for each 10 µg/m3 SO2 increase at 8-h time lag and a strong dose-response relation. Exposure to SO2 is strongly associated with reduction of lung function and an increase in airway inflammation. This new evidence of harmful effects of SO2 peaks should induce regulatory intervention.