Acute effects of air pollutants on pulmonary function among students: a panel study in an isolated island

Background: Many epidemiological studies on the health effects of air pollutants have been carried out in regions with major sources such as factories and automobiles. However, the health effects of air pollutants in regions without major sources remain unclear. This study investigated the acute effects of ambient air pollution on pulmonary function among healthy students in an isolated island without major artificial sources of air pollutants. Methods: A panel study was conducted of 43 healthy subjects who attended a school in an isolated island in the Seto Inland Sea, Japan. We measured the forced expiratory volume in 1 s (FEV1) and peak expiratory flow (PEF) every morning for about 1 month in May 2014. Ambient concentrations of particulate matter <= 2.5 mu m in diameter (PM2.5), particulate matter between 2.5 and 10 mu m in diameter (PM10-2.5), black carbon (BC), ozone (O-3), and nitrogen dioxide (NO2) were measured. The associations between the concentrations of air pollutants and pulmonary function were analyzed using mixed-effects models. Results: A decrease in FEV1 was significantly associated with BC concentrations (-27.28 mL [95% confidence interval (CI): -54.10,-0.46] for an interquartile range (IQR) increase of 0.23 mu g/m(3)). The decrease in PEF was significantly associated with indoor O-3 concentrations (-8.03 L/min [95% CI:-13.02,-3.03] for an IQR increase of 11 ppb). Among subjects with a history of allergy, an increase in PM2.5 concentrations was significantly associated with low FEV1. In subjects with a history of asthma, an inverse association between the indoor O-3 concentration and pulmonary function was observed. Conclusions: Our results demonstrate that increases in BC and O-3 concentrations have acute effects on the pulmonary function among students in an isolated island without major artificial sources of air pollutants.