Coal has historically been a primary energy source in the United States (U.S.). The byproducts of coal combustion, such as fine particulate matter (PM_2.5), have increasingly been associated with adverse birth outcomes. The goal of this study was to leverage the current progressive transition away from coal in the U.S. to assess whether coal PM_2.5 is associated with preterm birth (PTB) rates and whether this association differs by maternal Black/White race/ethnicity. Using a novel dispersion modeling approach, we estimated PM_2.5 pollution from coal-fired power plants nationwide at the county-level during the study period (2000–2018). We also obtained county-level PTB rates for non-Hispanic White and non-Hispanic Black mothers. We used a generalized additive mixed model to estimate the relationship between coal PM_2.5 and PTB rates, overall and stratified by maternal race. We included a natural spline to allow for non-linearity in the concentration–response curve. We observed a positive non-linear relationship between coal PM_2.5 and PTB rate, which plateaued at higher levels of pollution. We also observed differential associations by maternal race; the association was stronger for White women, especially at higher levels of coal PM_2.5 (>2.0 μg m⁻³). Our findings suggest that the transition away from coal may reduce PTB rates in the U.S.

煤炭在历史上一直是美国 (US) 的主要能源。煤炭燃烧的副产品，例如细颗粒物 (PM _2.5 )，与不良出生结局的关联越来越大。本研究的目的是利用美国当前从煤炭的逐步过渡来评估煤炭 PM _2.5是否与早产 (PTB) 率相关，以及这种相关性是否因母体黑人/白人种族/民族而异。我们使用一种新的扩散建模方法，估计了 PM _2.5研究期间（2000-2018年）全国县级燃煤电厂污染情况。我们还获得了非西班牙裔白人和非西班牙裔黑人母亲的县级 PTB 率。_{我们使用广义添加剂混合模型来估计煤 PM 2.5}和 PTB 率之间的关系，总体上按母体种族分层。我们包括一个自然样条曲线，以允许浓度 - 响应曲线中的非线性。_{我们观察到煤炭 PM 2.5}与 PTB 率之间呈正非线性关系，在较高污染水平时趋于稳定。我们还观察到母系种族的不同关联；_{白人女性的相关性更强，尤其是在煤 PM 2.5}水平较高时（>2.0 μ g m^-3 )。我们的研究结果表明，从煤炭的转变可能会降低美国的 PTB 率