As the U.S. Environmental Protection Agency (EPA) moves to dismantle the Clean Power Plan touting a return to "cooperative federalism," the results of a new study focused on the downwind impact on fetal health of emissions from a coal-fired power plant, which is located on the border between two states, highlight policy gaps engendered by state-level regulation of air pollution.

The reason? Wind does not recognize state borders.

The Portland Generating Station, a coal-fired power plant in Pennsylvania located right on the New Jersey border, was shut down in June 2014 as a result of a landmark EPA ruling identifying the plant as a sole pollution source damaging the air quality in the downwind state New Jersey -- the first-ever federal level regulation under the Clean Air Act to have overridden state-level regulations on a single pollution source. In a recent study, two Lehigh University faculty members Muzhe Yang, Associate Professor of Economics and Shin-Yi Chou, Professor and Chair of the Economics Department -- compared birth outcomes of fetuses conceived after the power plant's shutdown with the birth outcomes of fetuses conceived before the shutdown to infer the health impacts of closing the plant.

Yang and Chou found that shutting down the plant reduced the likelihood of having a low birth weight baby by 0.89 percentage points or about 15 percent, and reduced the likelihood of a preterm birth by 2.83 percentage points or about 28 percent, in areas downwind of the power plant. These effects are largely seen in babies conceived in New Jersey zip codes located within 60 miles of the plant.

Their analysis examined the power plant's emission data from the year and half immediately after the plant shutdown, June 2014 to December 2015, a period during which sulfur dioxide emissions were nearly zero. They compared them to the emission data from a year and a half period before the shutdown at the time when sulfur dioxide emissions remained consistently high at 2,596.648 tons per month, from June 2008 to December 2009. After the plant shut down, sulfur dioxide emissions dropped by 99.9988 percent.

"Our study is the first to show fetal health improvement as a result of shutting down a large air polluter leading to a drastic reduction of [sulfur dioxide] emissions," write the authors in a paper published online today in the Journal of Environmental Economics and Management, which will appear in an upcoming print edition.

The border location of the Portland Generating Station highlights a gap in federal air pollution regulation, which appears to foster a disparity between the impacts of a plant on the upwind and downwind states. The upwind state reaps the benefits of the plant through job creation and tax revenue, while the downwind state pays the pollution costs -- due to wind.

According to Yang and Chou, their study ." ..examines a case where cross-border air pollution had not been effectively dealt with by a decentralized, state level policymaking, letting a coal-fired power plant located on the border between two states pollute the downwind state for years without being controlled."

In a companion study published in April 2017, Yang and Chou (together with Bhatta and Hsieh) found that babies born during 1990-2006 (well before the shutdown of the power plant) to mothers living as far as 20 to 30 miles away from the power plant had 6.5 percent greater risk of low birth weight and 17.12 percent greater risk of very low birth weight.