Recent Projects

Nitrogen oxides (NOx) are a precursor to ground-level ozone, a pernicious pollutant that is harmful to human health and ecosystems. Despite decades of regulations and a sharp decline in NOx emissions, episodic high-ozone events prevent many areas from attaining air quality standards. Theoretically, spatially or temporally differentiated emissions prices could be more cost effective at reducing such events than a uniform price. To test this prediction, with data from EPA and NOAA spanning 2001–2019, this working paper uses novel empirical strategies to estimate (1) the link between hourly emissions and high-ozone events and (2) hourly marginal abatement costs. These estimates form the basis for simulations that compare uniform and differentiated emissions pricing. Consistent with economic theory, differentiated pricing is substantially more cost effective at reducing high-ozone events, but this advantage depends on the accuracy of the estimated NOx–ozone relationship.

While vintage differentiation is a highly prominent feature of various regulations, it can induce significant biases. We study these biases in the context of New Source Review—a program within the US Clean Air Act imposing costly sulfur dioxide (SO2) abatement requirements on new boilers but not existing ones. In particular, we empirically investigate how the differential treatment of coal boilers shaped the generation landscape by affecting unit utilization, retirement, and emissions. Focusing solely on the additional SO2 emissions, we estimate annual costs of up to $65 billion associated with the vintage differentiation in New Source Review.

The article examines the failures of the U.S. Environmental Protection Agency to address the environmental justice harms from air pollution and identifies three recent development that could augur beneficial change.

EPA is considering regulations that would clean up the wastewater discharges from power plants, after they were stalled and then rolled back under the Trump administration. As it conducts that analysis, this report urges EPA to provide a robust assessment of the benefits of the regulation, improving on analysis that was conducted in the Obama era. The report reviews the economic framework, literature, and analyses performed to support both the original Obama-era rule and Trump-era revisions, building on Davis Noll and Rothschild (2021), which detailed numerous impacts of the 2020 Rule that EPA neglected to examine. This review highlights key considerations that will strengthen future regulations. 

This report identifies best practices EPA should adopt to holistically assess and weigh the costs and benefits of risk management options, allowing the agency to meet its statutory obligations and best enhance public welfare.