Expert on Camera:
School districts across the country are replacing diesel buses with electric ones, with many districts using funds from the Environmental Protection Agency’s $5B Clean School Bus Program and/or state funding.
On Tuesday, August 13, 2024, SciLine interviewed: Dr. Sara Adar, an associate professor of epidemiology at the University of Michigan. See the footage and transcript from the interview below, or select ‘Contents’ on the left to skip to specific questions.
Introduction
[0:00:19]
SARA ADAR: My name is Sara Adar and I’m a professor at the University of Michigan School of Public Health. My expertise is on studying air pollution and noise and health.
Interview with SciLine
What are the health effects of emissions from diesel vehicles?
[0:00:36]
SARA ADAR: The emissions from diesel exhaust are broadly damaging to our health. For example, diesel exhaust has been known to be linked to increased risks of asthma, overall poor lung health, and even difficulties in concentrating.
Why are school buses such a concerning source of pollution?
[0:00:59]
SARA ADAR: Diesel exhaust is especially concerning for children because many school buses create very high levels of air pollution inside those buses and in the immediate vicinities while they’re idling or, you know, waiting at a school bus stop. And this can be problematic because on these buses that have very high levels of pollution, kids can experience about half of their daily exposures to air pollution, just from riding to and from school.
Why are children so vulnerable to the harmful effects of diesel exhaust?
[0:01:39]
SARA ADAR: There are several reasons that children are especially vulnerable to diesel exhaust. The first is that they’re still developing right, so as their lungs are growing and they’re getting stronger, you know, the pollution can really damage that process and set them up for worse lung function over their lifetime. Second, kids actually breathe in more air per their body sizes than grown-ups do. And finally, kids are also often shorter than many of us grown-ups, and so when they’re waiting at a bus stop, they’re much closer to the tailpipe emissions of a vehicle than many adults are.
When children switch to riding cleaner buses, how are they affected?
[0:02:26]
SARA ADAR: One study that we did in about 400 kids from Seattle, Washington, was looking at the health of kids as their districts replaced their older buses with cleaner and less polluting buses. What we found in that study was that the kids, while they were riding those cleaner buses, they had better lung health—so less inflammation in their lungs—and they were less likely to miss school or be absent than the times when they were on the dirtier buses.
Can you tell us about your research on the district-wide effects when a school district switches to cleaner buses?
[0:03:06]
SARA ADAR: What we studied was the EPA’s investment in purchasing new school buses for districts that applied for funds. What we saw in that study was that the districts who applied for funds and were rewarded the money in a random lottery. Those districts saw better attendance of their children as well as better educational attainment of the children—so they basically tested better on all those standardized test scores—than the districts who also asked for money but were not selected for those funds to replace their buses.
Why is replacing older diesel buses so important?
[0:03:07]
SARA ADAR: A really important aspect of our work was the finding that it’s the oldest buses to replace that really make the biggest impact. And when I’m talking about older buses, what I’m talking about is buses that are really from the early 2000s and before. And the reason that those buses are so important to replace is that after 2007, the EPA changed their standards for new buses that made them cleaner, and so it’s those oldest buses that don’t have any of the modern cleaner technology that really have higher pollution levels on board than the newer vehicles.
Considering the negative health effects, should our society reconsider the use of school buses?
[0:04:42]
SARA ADAR: So, one thing that’s important to keep in mind when we’re talking about the impact of diesel exhaust on kids health with riding school buses is that school buses still remain the safest way to get kids to and from school. From a population perspective, it’s also beneficial because you’re taking all the cars off the road and getting kids to school efficiently. So, even though there are health impacts of kids riding really old school buses to and from, you know, their education, I want to make sure that it’s clear that school buses in general still have a benefit to our society.
Do you have advice for communities where children are still riding older diesel school buses?
[0:05:32]
SARA ADAR: So, one other thing that I’d like to raise to people’s attention is that the EPA and the U.S. government have invested a great deal of resources in helping school districts to replace their older buses with cleaner vehicles, and so I encourage communities who have very old vehicles, so from 2000 and earlier, to consider applying for these funds. Each year, the government has been spending about $1 billion and have been replacing about 3000 vehicles for schools around the country.
