A study conducted by researchers at Harvard T.H. Chan School of Public Health has found that replacing diesel school buses with electric school buses can result in significant climate and health benefits. The researchers estimated that each electric bus could yield up to $247,600 in savings, including reduced greenhouse gas emissions and lower rates of adult mortality and childhood asthma. These benefits were found to be most pronounced in large cities and among fleets of older buses, particularly those manufactured in 2005 or earlier.
The study, set to be published in The Proceedings of the National Academy of Sciences, is the first of its kind to specifically quantify the positive impacts of electric school buses on human and planetary health. Senior author Kari Nadeau emphasized the importance of quantifying health benefits when considering solutions to reduce greenhouse gas emissions and air pollution. The findings of the study provide evidence to policymakers that transitioning to electric vehicles, especially school buses, can have significant positive effects on individual, public, and planetary health.
With approximately half a million school buses currently in operation in the United States, a substantial number of these are old, highly polluting diesel buses. The decision to switch to electric buses can be challenging due to the associated costs and limited awareness of the health benefits. To assess the impact of diesel and electric buses on the climate, the researchers compared the carbon dioxide emissions from diesel bus tailpipes to those produced during the generation of electricity and battery production for electric buses. For health considerations, they examined how emissions from each type of bus contribute to fine particulate air pollution (PM2.5), which is linked to increased mortality rates and childhood asthma.
The study revealed that replacing an average diesel school bus with an electric one in 2017 could result in $84,200 in benefits per bus. Each electric bus emitted 181 fewer metric tons of carbon dioxide, translating to $40,400 in climate benefits. Additionally, the health savings associated with each electric bus were estimated at $43,800, owing to reduced air pollution and lower rates of mortality and childhood asthma. The researchers also found that the health benefits of electric buses varied depending on the location and age of the diesel bus being replaced, with large metropolitan areas showing the most significant improvements in air quality.
In dense urban settings, where older diesel buses are prevalent in school bus fleets, the authors noted that the financial savings from transitioning to electric buses outweigh the costs of replacement. This transition is particularly beneficial for racial minorities and low-income communities that are disproportionately affected by the health risks of air pollution. However, the study did not address the impact of electric school buses on children’s exposure to in-cabin air pollution while riding the bus, suggesting the need for additional research in this area to better inform policy decisions. Co-authors Ernani Choma and Lisa Robinson were also part of the research team.