While electrifying trucks slashes diesel emissions, new research reveals a stark reality: pollution burdens shift to power plants, keeping disadvantaged communities at risk. Can targeted strategies close the gap?
Study: Impact of truck electrification on air pollution disparities in the United States. Image Credit: Scharfsinn / Shutterstock
In a recent study published in the journal Nature Sustainability, a group of researchers evaluated the impact of heavy-duty truck electrification and grid decarbonization on air pollution disparities among disadvantaged communities and racial-ethnic groups in the United States.
Background
Air pollution is a persistent public health challenge, disproportionately affecting marginalized communities. Heavy-duty diesel trucks contribute significantly to particulate matter (PM2.5) and nitrogen oxide (NOx) emissions, exacerbating respiratory and cardiovascular diseases.
In the United States, truck emissions disproportionately burden disadvantaged communities, often located near major freight corridors and industrial zones.
Exposure to transportation-related air pollutants results in thousands of premature deaths annually, with historically marginalized racial-ethnic groups suffering the highest health burdens.
Policies such as the Inflation Reduction Act (IRA) and the Justice40 Initiative aim to reduce pollution through truck electrification and grid decarbonization. However, the net effect on air pollution inequality remains unclear.
Prior studies have examined regional impacts, but a comprehensive national assessment of air pollution disparities under full truck electrification is still needed to guide equitable policy development.
About the Study
This study utilized a national-scale analysis to compare air-pollution-related health impacts from diesel and electric heavy-duty trucks under different grid decarbonization scenarios.
The research modeled truck traffic flows, emissions, and their associated health impacts through an integrated framework. Truck movement data were derived from the Freight Analysis Framework (FAF), accounting for projected increases in freight volume through 2050.
The study modeled emissions from Class 8 diesel trucks, which were compared to estimated grid emissions from electric truck charging loads under varying renewable energy scenarios.
Emission estimates for diesel trucks were based on real-world measurements and incorporated pollution control technologies.
For electric trucks, hourly charging demand was fed into a grid model leveraging the National Renewable Energy Laboratory (NREL) Standard Scenarios, which identified the marginal electricity generators meeting additional loads.
The InMAP Source-Receptor Matrix (ISRM), a reduced-form air quality model, was used to estimate air pollution concentrations and associated health damages for both diesel and electric trucks.
Air pollution exposure disparities were assessed by calculating absolute and relative differences, which the study found increased over time, from 0.7% to 6.9%, in PM2.5 concentrations between disadvantaged and non-disadvantaged communities as well as across racial-ethnic groups.
Study Results
The study found that truck electrification significantly reduces overall air pollution-related premature mortality in disadvantaged communities.
However, the relative disparity between disadvantaged and non-disadvantaged communities increases steadily over time, with non-disadvantaged populations receiving a greater share of the benefits.
In a fully electrified truck scenario, disadvantaged communities continue to experience higher pollution exposure than their share of the general population despite absolute reductions in mortality rates.
Under low renewable energy cost scenarios, the IRA’s incentives accelerate grid decarbonization, leading to an 84% reduction in premature mortality in disadvantaged communities by 2050.
In contrast, under high renewable energy cost scenarios, reductions in premature mortality are lower, and disparities persist. Even with extensive decarbonization, the Black population remains the most exposed racial-ethnic group, experiencing a decline in absolute exposure but continuing to face disproportionately high pollution levels relative to other groups.
The results suggest that electrifying drayage corridors, which involve short-haul truck routes near urban centers and ports, yield greater immediate health benefits for disadvantaged communities than uniform truck electrification across all corridors.
Currently, 95% of drayage vehicle miles traveled (VMT) already provide net health benefits for disadvantaged communities, compared to only 33% of long-haul VMT.
By 2030, targeted electrification of drayage trucks will result in 100% net health benefits for disadvantaged communities, whereas long-haul corridors will see an increase of only 84%.
Despite reductions in absolute disparities, only 20% or less of the benefits of truck electrification accrue in disadvantaged communities under a low renewable energy cost scenario, highlighting ongoing inequities.
The study found that marginal grid emissions from truck charging loads still disproportionately affect Black communities. While truck electrification shifts emissions away from highways, power plants supplying electricity are disproportionately located near disadvantaged communities, exacerbating exposure disparities.
Specifically, the study identified 91 high-emission power plants expected to ramp up due to electric truck charging loads, with 71 located within five miles of disadvantaged communities. Addressing emissions from these plants through additional regulatory measures could help mitigate inequities.
The findings indicate that broad truck electrification alone is insufficient to achieve the Justice40 Initiative’s goal of directing 40% of benefits to disadvantaged communities.
To maximize equity, a targeted approach prioritizing high-emission corridors and urban freight routes is suggested. Electrifying high-density drayage corridors near ports and urban areas provides a greater share of benefits to marginalized communities compared to indiscriminate long-haul electrification.
However, the study also highlights a policy trade-off: while truck electrification reduces highway emissions, it increases demand on power plants, which could lead to pollution burdens shifting rather than disappearing.
Conclusions
To summarize, truck electrification and grid decarbonization reduce air pollution exposure for all populations, improving overall public health outcomes. However, relative disparities persist, with non-disadvantaged communities benefiting more than disadvantaged ones.
The findings suggest that a uniform electrification strategy is inadequate for achieving environmental justice. Targeted investments in electrifying drayage trucking corridors and mitigating emissions from power plants near marginalized communities are essential to ensure equitable air quality improvements.
The study also acknowledges certain limitations, including the challenge of predicting long-term population shifts and the environmental justice concerns associated with battery manufacturing for electric trucks.
Policymakers should consider location-specific strategies to maximize the benefits of electrification for disadvantaged communities while addressing persistent racial-ethnic disparities in air pollution exposure.