Carnegie Mellon University
December 08, 2022

Equality and air quality: the decarbonization balancing act

Sustainability is the driving factor behind decarbonization, as it’s widely understood that an energy system rooted in fossil fuels will have disastrous outcome for human health and our planet. However, when modeling decarbonization, sustainability is far from the only consideration policymakers must make. Potential pathways to decarbonization are often evaluated on a least cost basis, as many national investments are.

Though decarbonization will provide a net benefit for every American, that doesn’t guarantee that these benefits will be evenly distributed across society as a whole. To investigate this potential for continued inequality, Destenie Nock, assistant professor of civil and environmental engineering and engineering and public policy, and Teagan Goforth, a graduate student in engineering and public policy, have created a new framework for social impact assessment to identify who may be burdened nationally with higher levels of air pollution during the energy transition.

While the entire country will enjoy the benefits of a fully carbon neutral energy grid, on our current course, the environmental benefits of getting there will likely be unevenly distributed. The new framework, recently published in Nature Communications, will help policymakers achieve equal distribution in air quality benefits as our energy system decarbonizes.

"We have shown that a single objective of minimizing cost doesn’t ensure equitable distribution of benefits in terms of local air pollutants."

“I hope that this will help move the decarbonization discussions towards considering the environmental and social lens,” says Nock. “This forward-looking equality analysis can help identify potential disparities before we build a new energy system.” 

Based on national strategies for decarbonization, Nock and Goforth modeled the regional impacts on energy generation and air quality across 134 regions of the United States. They matched this with corresponding census data, overlaying demographic information with the annual distribution of airborne pollutants from energy generation predicted in a given region, based on the decarbonization strategy in question.

Across the eight decarbonization scenarios evaluated within their framework, they found that none achieved equality in air quality before their mandated year for decarbonization, whether it was 2035 or 2050. Every scenario involving at least some future decarbonization efforts would reduce air pollutants for the lowest income group by at least 20 percent; however, inequalities persisted in every scenario. This held true across every demographic factor they evaluated, including income group, poverty level, and race/ethnic background.

Nock and Goforth concluded from their analysis that any decarbonization scenario based solely on the least-cost paradigm is at risk of allowing local air pollution inequalities to persist. The framework they’ve created to analyze equality in the distribution of air pollution can help policymakers as they work through a difficult balancing act with numerous economic, environmental, technical, and social factors. The authors contend that to prioritize equal distribution in air quality, our pathway to decarbonization must be guided by strict mandates, or be consistently driven by a focus on equality throughout the energy transition.

“We have shown that a single objective of minimizing cost doesn’t ensure equitable distribution of benefits in terms of local air pollutants. Air pollution disparities need to be considered throughout the transition,” says Nock. “When crafting public policy for energy transitions, decision-makers can use this work as a source for indicating the need for holistic multiple objective approaches to energy system planning and to ensure an equitable and sustainable future.”

Noting several opportunities for further investigation, Nock and Goforth question how outcomes might differ from an assessment based on optimizing equality, rather than minimizing cost. There’s also room for expanding their analysis to consider potential trade-offs between equal air pollution distribution and other equality, equity, environmental, and cost objectives. A multidisciplinary perspective will be crucial to managing this complicated array of trade-offs.

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