A panel study of airborne particulate matter composition versus concentration: Potential for inflammatory response and impaired pulmonary function in children

BackgroundThe relationship between airborne particulate matter (PM) and pulmonary function in children has not been consistent among studies, potentially owing to differences in the inflammatory response to PM, based on PM types and sources. The objective of this study was to investigate the effect of airborne PM on pulmonary function in schoolchildren and its potential for an inflammatory response.MethodsDaily morning peak expiratory flow (PEF) was measured in 339 schoolchildren in February 2015. Interleukin (IL)-8 production was assessed in THP1 cells stimulated by airborne PM collected every day during the study period, and these IL-8 concentrations are described as the daily IL-8 levels. A linear mixed model was used to estimate the association between PEF values and the daily levels of suspended PM (SPM), PM diameters smaller than 2.5 μm (PM2.5), and IL-8.ResultsThe daily IL-8 levels were significantly associated with those of SPM and PM2.5. A 0.83 μg/mL increase in IL-8 levels was significantly associated with a −1.07 L/min (95% confidence interval, −2.05 to −0.08) decrease in PEF. A 12.0 μg/m3 increase in SPM and a 10.0 μg/m3 increase in PM2.5 were associated with a −1.36 L/min (−2.93 to 0.22) and −1.72 L/min (−3.82 to 0.36) decreases in PEF, respectively. There were no significant relationships between PEF, SPM, and PM2.5.ConclusionsThese findings suggest that the effects of airborne PM on pulmonary function in schoolchildren might depend more on the pro-inflammatory response than the mass concentration of the PM.