Michael Ash

We evaluate how the availability of carbon capture (CC) in a networked electricity system affects the emissions of both carbon and of co-pollutants, under a range of plausible technical, economic, and policy scenarios about CC technology, the pace of renewable deployment, the structure of the power grid, and climate policy. We employ a Power Flow model of a three-node, mixed-source network in which fossil fuel power plants may invest in CC via retrofit. Our stylized model retains some of the complexities of a real power system while allowing for a detailed analysis of the impact of power plant operations and transmission constraints. We find that, in a networked system, the availability of CC may lead some generation to move from natural gas to coal, thus leading to a significant increase in co-pollutants. This is of particular concern during the mid-transition, a period when both carbon and non-carbon electrical generation is active. The introduction of CC can lead to an increase in co-pollution even as the energy system transitions toward renewable energy and, surprisingly, co-pollution outcomes can be worse under a stronger decarbonization policy. This insight is important and timely in light of recent rules incentivizing the use of CC. Systems in the early stages of the energy transition may experience an increase in co-pollution if the co-pollutant dynamics are not considered in the first steps of CC policy design.

Environmental inequalities are often large and consequential, exacerbating vertical inequalities of income and class and horizontal inequalities along lines of race and ethnicity. Climate policies can widen these inequalities as well as mitigate them, depending on their design. Decarbonization of the US electricity sector illustrates these possibilities. A strategy narrowly focused on carbon reduction alone is likely in some regions to increase disparities in exposure to localized co-pollutants emitted by fossil fuel combustion and, in some cases, to increase exposure in absolute terms. Strategies that in addition explicitly mandate improvements in air quality, both overall and specifically for frontline communities, can couple decarbonization with remediation of environmental inequalities and broad-based gains in public health.

Wu et al. found a strong positive association between cumulative daily county-level COVID-19 mortality and long-term average PM_2.5 concentrations for data up until September 2020. We replicated the results of Wu et al. and extended the analysis up until May 2022. The association between PM_2.5 concentration and cumulative COVID-19 mortality fell sharply after September 2020. Using the data available from Wu et al.’s “updated_data” branch up until May 2022, we found that the effect of a 1 μg/m³ increase in PM_2.5 was associated with only a +0.603% mortality difference. The 95% CI of this difference was between −0.560% and +1.78%, narrow bounds that include zero, with the upper bound far below the Wu et al. estimate. Short-term trends in the initial spread of COVID-19, not a long-term epidemiologic association, caused an early correlation between air pollution and COVID-19 mortality.

The PerformanceStat approach to performance management emphasizes leadership involvement, top-down accountability routines, and rapid application of data, a configuration likely to improve measured outcomes in targeted areas but with high risk of adverse effects in non-targeted or neglected areas, such as equity and social justice. We test these hypotheses in examining the impact of CompStat policing on crime reduction, the intended target, and on racial disparities in arrest rates, a neglected consequence. Event-history analysis and semi-parametric controls of 14 years of data for a nationwide sample of U.S. police departments in small- to medium-size cities find that CompStat is associated with some reduction in crime, with variation across crime types and the indication of distinct prior trends for adopters. At the same time, CompStat significantly increases the risk of arrests among blacks, especially juveniles, supporting concerns about the adverse unintended consequences.

Article Review of Foundations of Real World Economics: What Every Economics Student Needs to Know (Komlos 2019) was published on December 1, 2020 in the journal Basic Income Studies (volume 15, issue 2).

Significance: Debate about regulation of industrial polluters often concerns a presumed trade-off between negative pollution impacts and positive employment opportunities. These arguments are especially sensitive among communities of racial/ethnic minorities, who disproportionately suffer exposure to pollution and lack access to high-quality employment. We combine US Environmental Protection Agency (EPA) data on toxics exposure with Equal Employment Opportunity Commission (EEOC) data on employment to examine how the racial/ethnic distribution of industrial employment corresponds to the distribution of exposure to air toxics emitted by the same facilities. The share of pollution risk accruing to minority groups generally exceeds their share of employment and greatly exceeds their share of higher paying jobs. In aggregate, we find no evidence that facilities that create higher pollution risk for surrounding communities provide more jobs.

In a Perspective, James Boyce and Michael Ash discuss Lara Cushing and colleagues' research study on the implications of California's policy on carbon trading.