Short-term effects of the chemical components of fine particulate matter on pulmonary function: A repeated panel study among adolescents

The effects of the chemical components of fine particulate matter (PM_2.5) have been drawing attention. However, information regarding the impact of low PM_2.5 concentrations is limited. Hence, we aimed to investigate the short-term effects of the chemical components of PM_2.5 on pulmonary function and their seasonal differences in healthy adolescents living on an isolated island without major artificial sources of air pollution. A panel study was repeatedly conducted twice a year for one month every spring and fall from October 2014 to November 2016 on an isolated island in the Seto Inland Sea, which has no major artificial sources of air pollution. Daily measurements of peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV₁) were performed in 47 healthy college students, and the concentrations of 35 chemical components of PM_2.5 were analyzed every 24 h. Using a mixed-effects model, the relationship between pulmonary function values and concentrations of PM_2.5 components was analyzed. Significant associations were observed between several PM_2.5 components and decreased pulmonary function. Among the ionic components, sulfate was strongly related to decreases in PEF and FEV₁ (-4.20 L/min [95 % confidence interval (CI): -6.40 to -2.00] and - 0.04 L [95 % CI: -0.05 to -0.02] per interquartile range increase, respectively). Among the elemental components, potassium induced the greatest reduction in PEF and FEV₁. Therefore, PEF and FEV₁ were significantly reduced as the concentrations of several PM_2.5 components increased during fall, with minimal changes observed during spring. Several chemical components of PM_2.5 were significantly associated with decreased pulmonary function among healthy adolescents. The concentrations of PM_2.5 chemical components differed by season, suggesting the occurrence of distinct effects on the respiratory system depending on the type of component.