New research from WRI’s Electric School Bus Initiative and Carleton University shows that the U.S. would see an estimated $1.6 billion in health and climate benefits every year by using electric school buses.
This estimate accounts for the cost to society of using diesel-burning school buses compared to electric school buses. The dollar amount is based on the premature mortality risk from exposure to harmful pollutants from diesel buses, as well as societal damage from those buses’ greenhouse gas emissions resulting in extreme heat, sea level rise, food insecurity and other impacts of climate change.
By comparing these costs at the local level, the data provides annual societal benefit figures for every county in the contiguous United States.
According to this research, people in every state analyzed would experience positive benefits from using electric school buses. Those benefits would be most pronounced in counties operating the oldest diesel-burning school buses — often in communities with higher proportions of people of color — and in counties with larger populations.
This research is among the first to model and quantify the county-level health and climate impacts of using electric school buses instead of aging diesel-burning school buses.
How Electric School Bus Benefits Were Calculated
The data looks at the impacts of continuing to use the current fleet of diesel-burning school buses in the 48 contiguous U.S. states, based on data availability, and compares them to electric school buses based on population health and climate change.
About 90% of the half a million school buses operating in the U.S. run on diesel fuel. Diesel exhaust contains harmful pollutants such as fine particulate matter (PM2.5), nitrogen oxides (NOx) and volatile organic compounds (VOCs). These pollutants can cause respiratory illness, cognitive impairment and cancer, as recognized by the World Health Organization. Older diesel-burning school buses don’t have modern emissions controls, so they emit even higher levels of pollutants, putting students, drivers and residents in greater danger.
Electric school buses, by contrast, produce zero tailpipe emissions and have the lowest greenhouse gas footprint of any school bus type at the national level, even when accounting for emissions from the associated electricity generation.
To estimate the effects of using electric school buses instead of diesel-burning school buses, this research looked at the impacts of diesel-burning school buses, both in their operation and in the production and distribution of the diesel fuel used.
That included:
- The health impacts of diesel-burning school buses. This was estimated by determining the excess mortality due to exposure to fine particulate matter caused by these school buses. These impacts were then calculated into dollar figures based on a sociological metric that looks at how much society is willing to pay for small reductions to the risk of dying from health conditions that may be caused by environmental pollution. The fine particulate matter is called PM2.5, and the sociological metric is called the Value of a Statistical Life.
- The climate impacts of diesel-burning school buses. This was measured by calculating the Social Cost of Carbon from these buses’ carbon dioxide (CO2) Social Cost of Carbon is an established metric for the societal damage from extreme heat, sea level rise, food insecurity, and other impacts of climate change.
Because health impacts were measured only by excess mortality from PM2.5, there are likely more health benefits of electric school buses that aren’t captured in this data, including reduced exposure to ozone pollutants, NOx and VOCs.
Once the societal costs of diesel-burning school bus impacts were determined, the research then calculated the same types of impacts for electric school buses, including from electricity generation, and compared them to diesel-burning school buses to provide an annual societal benefit figure in dollar amounts for each county.
The research used a new modeling approach to estimate these impacts specifically for diesel-burning school bus pollution by tracing air pollution back to its source. The research uses state-of-the-art models and county-level data to more specifically estimate where electric school buses would provide the most health and climate benefits through reduced emissions. It doesn’t look at the cost to own or operate different types of school buses, instead examining the impact on society from the use of the buses.
Findings Show Nationwide Benefits
This new research demonstrates the health and climate benefits of using electric school buses in every part of the country — and the current harms caused by diesel-burning school buses.
Electric school buses offer substantial health and climate benefits in all regions, all states and 99.7% of counties in the contiguous U.S. All told, using electric school buses would produce an estimated $1.6 billion in societal benefits annually in the U.S.
New York, California, Texas and Florida are the states poised to benefit the most from school bus electrification, with additional states in the Northeast, South, West and Midwest all projected to see significant benefits. Larger populations and dense, urban areas experience increased benefits since reductions in harmful emissions affect more people.
While the annual benefits vary by county — based on the school bus fleet size, population density, electricity fuel-type mix and the age of the current diesel fleet — it’s clear that the benefits of using electric school buses would be felt at the local level in every part of the country.
Targeting the Oldest Buses Delivers the Greatest Benefits
Notable health benefits occur from using electric school buses in communities with older diesel-burning school buses that emit even higher levels of harmful pollution — vehicles that are disproportionately located in districts with higher shares of residents of color and low-income households.
The most polluting 10% of diesel-burning school buses are responsible for nearly 50% of the total health impacts of diesel-burning school buses nationwide. The cost of per-mile health impacts from diesel-burning school buses vary widely — from under $10 to nearly $4,000 per 1,000 miles, depending on the age and location of the school bus.
When looking only at the health benefits of using electric school buses instead of diesel-burning school buses — not accounting for the climate benefits — we can see where the health impacts would be most significant.
Expanding the Analysis Can Measure All Health Benefits
The research focused only on premature mortality from fine particulate matter (PM2.5) as the primary health endpoint given the metric’s well-established use in pollution-health impact research.
However, diesel-burning school buses also emit large amounts of nitrogen oxide, which contributes to ozone formation and nitrogen dioxide exposure — both are linked to asthma, morbidity and additional premature deaths.
Because this new research doesn’t include these additional health effects, or the health impacts of other diesel pollutants like volatile organic compounds, there are probably even more health benefits of using electric school buses than this data shows.
Incorporating nitrogen oxide related outcomes in future modeling would likely show even greater contrasts between electric school buses and diesel-burning school buses.
Capturing the Opportunity Requires Specific Action
Using electric school buses would bring positive health and climate benefits to nearly every U.S. county, making it a win for communities nationwide.
The greatest equity and public health gains come from targeting the oldest diesel-burning school buses, which are disproportionately found in low-income communities and communities of color. Larger, more densely populated areas would especially see improvements, underscoring the positive impact of using electric school buses in urban and suburban areas.
As a result, using electric school buses in densely populated areas would maximize the benefits, because more people would be avoiding harmful diesel exposure. Funding should also prioritize districts with high shares of vulnerable populations and outdated school buses.
Furthermore, future analyses that include ozone- and nitrogen dioxide-related health impacts would likely reveal even greater advantages to electrification. This strengthens the case for urgent policy action at the local, state and federal levels to create funding and other support programs that aid school districts in the transition to electric school buses.
This article originally appeared on WRI’s Insights.
Brian Zepka is Research Manager for the Electric School Bus Initiative at WRI Ross Center for Sustainable Cities.
Amy Todd is Monitoring, Evaluation, Learning & Research Lead for the Electric School Bus Initiative at WRI Ross Center for Sustainable Cities.
