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(2.5)), ≤10 μm (PM(10)) and nitrogen dioxide (NO(2)) 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(2) 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(2) 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(2) 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(2.5), PM(10) and NO(2) on PTB were significant and greater in the cold season than the warm season. CONCLUSIONS: Maternal exposure to NO(2), PM(2.5) and PM(10) KEY MESSAGES: Maternal exposure to NO(2) was significant associated with an increased risk of preterm birth at the day 1 before delivery. Particle matter (PM(2.5) and PM(10)) 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.