Short-term effects of air pollution exposure on the risk of preterm birth in Xi'an, China.

Introduction: Long-term exposure to air pollution is known to be harmful to preterm birth (PTB), but little is known about the short-term effects. This study aims to quantify the short-term effect of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM), ≤10 μm (PM) and nitrogen dioxide (NO) on PTB.

Materials And Methods: A total of 18,826 singleton PTBs were collected during the study period. Poisson regression model combined with the distributed lag non-linear model was applied to evaluate the short-term effects of PTBs and air pollutants.

Results: Maternal exposure to NO was significantly associated increased risk of PTB at Lag1 (RR: 1.025, 95%CI: 1.003-1.047). In the moving average model, maternal exposure to NO significantly increased the risk of PTB at Lag01 (RR: 1.029, 95%CI: 1.004-1.054). In the cumulative model, maternal exposure to NO significant increased the risk of PTB at Cum01 (RR:1.026, 95%CI: 1.002-1.051), Cum02 (RR: 1.030, 95%CI: 1.003-1.059), and Cum03 (RR: 1.033, 95%CI: 1.002-1.066). The effects of PM, PM and NO on PTB were significant and greater in the cold season than the warm season.

Conclusions: Maternal exposure to NO, PM and PM before delivery has a significant risk for PTB, particularly in the cold season.Key messagesMaternal exposure to NO was significant associated with an increased risk of preterm birth at the day 1 before delivery.Particle matter (PM and PM) showed a significant short-term effect on preterm birth in the cold season.The effects of air pollutants on preterm birth was greater in the cold season compared with the warm season.