Do Electric School Buses Have an Impact in the Classroom?

Policy experts have studied the many social determinants of health for years. Most researchers agree that a person’s health is dependent on his or her social and physical environment. Many studies have examined how repeated exposure to air pollution increases the risk of developing asthma and pneumonia. School buses, which about 25 million children in the United States ride to school every morning, are a major source of this pollution. A recently published study suggests that these buses are negatively impacting not only students’ health but also their academic achievement.

In this 2019 study, policy researchers at Georgia State University examine the link between school bus diesel emissions and student outcomes. Some school districts in Georgia have retrofitted some or all of their school buses to dramatically reduce diesel emissions. The researchers collect information about when and where these retrofitting programs were implemented and then examine this data alongside measures of academic achievement and student health. Their academic metrics use data from statewide end-of-grade assessments, while their health metrics are based on scores from an aerobic capacity test administered in physical education classes.

The researchers’ analysis reveals two notable trends. First, districts that retrofitted more buses see a significant increase in respiratory health. This finding is especially strong among elementary-age students. Perhaps more surprisingly, those districts also demonstrate a significant increase in English test scores. This increase in test scores is so dramatic that the authors compare it to the impact of an experienced teacher (another study found similar shifts in test scores when comparing the outcomes of first-year teachers and fifth-year teachers). In other words, these results suggest that retrofitting diesel school buses is not only beneficial for students’ health but also improve their academic outcomes.

However, researchers had to address the consideration that districts which chose to retrofit their buses might be different from other districts in the first place. For instance, the retrofitting districts might also invest in other programs that influence student health and achievement. To account for this problem, the researchers collect information about students’ body mass indexes (BMI), since this health-related measure is not expected to change with air pollution exposure. They do not observe a change in BMI, suggesting that the changes in aerobic health are not due to an overall shift in student health. This finding suggests that the link between emissions and test scores was causal, meaning retrofitting school buses might have actually brought about the positive impacts.

The authors of the study emphasize the policy implications of these results. Policymakers are already encouraged to retrofit school buses or invest in electric school buses because of the environmental benefits, and previous research has already demonstrated that reducing pollution can improve health. However, this study is the first to also draw a link between reducing school bus emissions and boosting academic success. Policymakers who want to find a way to increase test scores might be able to impact three issues at once — pollution, health, and student success — by simply improving their school buses. The study’s authors also point out that retrofitting buses is a relatively affordable initiative compared to other interventions (such as reducing class sizes) aimed at improving test scores.

To determine the true merits of these policy changes, a state that is ready to invest in retrofitting buses could team up with researchers to construct a controlled experiment. By randomly choosing which districts to fund and observing their outcomes, policymakers would be able to better understand the impacts of bus-retrofitting programs.

For more on the transition to electric school buses, see Electric School Buses Are Flipping the Traditional Electricity Model on Its Head.

Article source: Austin, Wes, et al. “School bus emissions, student health and academic performance,” Economics of Education Review 70 (2019): 109-126.

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