Prenatal exposure to air pollution and the risk of preterm birth in rural population of Henan Province

Guoyu Zhou, Jingjing Wu, Meng Yang, Panpan Sun, Yongxiang Gong, Jian Chai, Junxi Zhang, Francis-Kojo Afrim, Wei Dong, Renjie Sun, Yuhong Wang, Qinyang Li, Dezhuan Zhou, Fangfang Yu, Yan Xi, Yawei Zhang, Lifang Jiang, Yue Ba