Riding the bus to and from school is a rite of passage for many kids and a huge timesaver for many parents. But if your kid’s bus has an old diesel engine, it can make it more difficult for them it to succeed in the classroom.
For the study, the researchers acquired data for 2,656 retrofits that happened across the state of Georgia between 2007 and 2017. A diesel retrofit can encompass any number of measures, from new filters and catalysts to the replacement of old buses ahead of schedule. All of these reduce emissions, some by up to 95 percent, and the fumes that kids breathe in while they’re in or around the bus.
Districts that retrofitted their buses saw a “sizable” increase in scores on aerobic capacity tests administered annually to all Georgia public school students enrolled in a P.E. class. Importantly, the study also showed the negative effects of bus fumes on kids without asthma or other respiratory conditions, making it the first study to do so.
When they turned their attention to academic performance, the researchers used performance on statewide tests in English language arts and math. They found that “retrofitting districts experience significant test score gains in English and smaller gains in math.”
Using estimates based on other studies, they found that the improvement is approximately the same as a student going from a first-year teacher to one with five years of experience. Retrofitting all of the school buses in a district is at least as effective as moving all students from a district with average air pollution levels to one with air pollution levels in the 10th percentile.”
The positive effects of diesel retrofits are also cost-effective both in and of themselves (the value of improved aerobic health they estimated is over ten times more than the cost of retrofitting) and compared to other school improvement measures (gaining a percentage point on state test performance is five times as expensive when done by reducing class size than it is by retrofitting buses).