Prenatal exposure to emissions from a coalmine fire and childhood lung function

BACKGROUND AND AIM: Studies linking early life exposure to air pollution and impaired lung health have focused on chronic, low-level exposure in urban settings. We have previously shown that early post-natal exposure to an acute, high-intensity air pollution episode was associated with mild impairments in peripheral lung mechanics. We aimed to determine whether in utero exposure to the same pollution event impaired lung function 7-years later. METHODS: We conducted a prospective study in a cohort of children who lived in the vicinity of a coalmine fire that burned for 6 weeks in 2014. Individual exposure to PM₂.₅ from the fire were estimated using dispersion and chemical transport modelling. Respiratory function was measured in children who were in utero during the fire, or conceived after the fire (unexposed), using the forced oscillation technique. Z-scores for resistance at 5Hz(R5), reactance at 5Hz(X5) and area under the reactance curve(AX) were calculated. Regression models were fitted to compare Z-scores of unexposed and in utero exposed children, and to examine the relationship between in utero PM₂.₅ exposure and lung function. RESULTS: Of the 72 children, 22 who were unexposed and 50 exposed in utero, and had acceptable lung function measurements. Medians (interquartile ranges) for daily average and peak PM₂.₅ for the children exposed in utero were 9.2(7.6–20.2) and 124(74–252) µg/m³. There were no statistically significant differences between mean R5, X5 or AX Z-scores of unexposed and in utero exposed children. There were no associations between R5, X5 or AX Z-scores and in utero exposure to daily average or peak PM₂.₅. This lack of association was maintained after inclusion of covariates in the models. CONCLUSION: There was no detectable effect of in utero exposure to PM₂.₅ from a local coalmine fire on post-natal lung function 7-years later. KEYWORDS: Particulate matter, respiratory function, early life, long-term effects