BACKGROUND: Ambient particulate pollution may adversely affect children's lung function. However, evidence on this association remains scarce in Asia despite this region having the greatest burden of disease due to air pollution.

OBJECTIVES: To investigate the effect of short-term exposure to ambient particulate matter (PM) on the lung function of school children in Dhaka city, Bangladesh. The possible seasonal modification of this association was also examined.

METHODS: A panel of 315 school children who were 9-16 years of age were recruited from three schools in and around Dhaka. Lung function was assessed using a spirometry test during the cool and warm seasons in 2013, yielding six measurements per child. Daily PM data were retrieved from nearby air monitoring stations. Linear mixed effects models were used to examine associations. Seasonal modification was examined by stratification.

RESULTS: An inverse association was observed for the lung function parameters with PM2.5; peak expiratory flow (PEF) and forced expiratory volume within 1 second (FEV1) decreased with increasing PM2.5. The percent deviation from the personal median was -4.19% [95% confidence interval (CI): -5.72, -2.66] for PEF and -2.05% (95% CI: -2.92, -1.18) for FEV1 for a 20 µg/m increase in PM2.5 on the previous day. Results for PM10 were less consistent. The estimated effects of PM on lung functions were generally greater in the warm season.

CONCLUSIONS: Short-term exposure to PM is associated with worse lung function in children living in highly polluted settings, with the strength of these adverse PM effects varying by season.