Exhaust Studies:Just Hot Air?
In the span of a week, the results of two major studies on school bus emissions were released and drew national attention. Both the Union of Concerned...
In the span of a week, the results of two major studies on school bus emissions were released and drew national attention. Both the Union of Concerned Scientists’ (UCS) “Pollution Report Card” and Yale professor Dr. James Wargo’s report challenged the safety of school bus fumes. Charlie Gauthier, executive director of the National Association of State Directors of Pupil Transportation Services (NASDPTS), has become a central figure in this debate after appearing on ABC’s “Good Morning America” to talk about the studies. He discussed with SBF PLUS the position of NASDPTS on this issue. SBF Plus: What is your take on these two recent emissions studies? Gauthier: In the last year, we’ve had four studies published on diesel school buses and the potential health effects on children. We had the one by the NRDC (Natural Resources Defense Council) that got this whole thing going. A couple of months later, a new one was done in Fairfax County, Va. Their conclusion was that diesel-powered school buses do not pose a health risk to students riding the bus. Then we had Dr. Wargo’s study. He concluded that in some instances children were exposed to five to 10 times dirtier air on the school bus. So after the UCS study, we still have people saying there is and people saying there isn’t a problem. I think we need to have a peer review by scientists who know what they are looking at and understand the data to find out if there really is a problem with diesel emissions. SBF Plus: How are the state directors reacting to these studies? Gauthier: Everybody feels the same way about it. You really don’t know who or what to believe. These studies were conducted by qualified organizations and individuals who seemed to follow approved or appropriate protocols. Yet, they each came up with very different conclusions. SBF Plus: What kinds of questions are the media asking you about this? Gauthier: They are all asking the same thing, which is: What should parents be thinking when they hear these reports? My standard response to them is that we have conflicting information from environmental health people. Common sense and good science says we have to figure out who’s right and who’s wrong before we go out and start scaring the public. SBF Plus: Is the media coverage fair and balanced on each side? Gauthier: I don’t know. I don’t think those are the right questions to ask right now. I think it’s good that the media is even asking us and airing our side. I’m not faulting them for ignoring us. Ideally, you would like more time to explain a bit more about your views, but at least our number one concern has been introduced and is sufficient to raise doubt about which side is correct. SBF Plus: Will this lead to major changes in school transportation? Gauthier: I really don’t know for sure at this time. For more information, go to http://www.nasdpts.org.
More Alternative Fuels

Fewer Electric School Bus Models Reshape the U.S. Market
WRI’s latest buyer’s guide points to a consolidating electric school bus market, but fewer options may reflect a maturing industry rather than fewer meaningful choices for school bus operators.
Read More →
The Fuel Budget You Can Actually Predict: How Propane Autogas Keeps Money in the Classroom
Learn how propane autogas helps school districts manage fuel costs with predictable pricing, lower maintenance, and reduced emissions from former transportation director Joel Stutheit.
Read More →
Hendrickson, Driventic Introduce New Electric Powertrain for School Buses
ELECTRAAX, the electrified, lightweight drive axle offers integrated ePowertrain efficiency and modular flexibility for Class 6–7 school bus use.
Read More →
The Mobility House Joins PowerFlex in Fleet Electrification Deal
The acquisition combines intelligent charging software, bidirectional charging expertise, and fleet electrification services to support the growing adoption of electric school buses across North America.
Read More →
Alt-Fuel Moves: Electric School Bus Investments Hit the Road
See which districts across the U.S. are putting electric school buses into service, expanding charging infrastructure, and planning the next phase of fleet electrification.
Read More →
With Fuel Volatility Ahead, School Districts Turn to Propane
While diesel prices peaked above $5 this spring, districts with propane autogas-powered fleets paid under $2 per gallon, according to PERC.
Read More →
EPA Unveils Proposed Changes to 2027 Heavy-Duty Engine Rules
The federal agency has proposed changes to next year’s targets that would eliminate DEF derates, ease warranty requirements, and retain current NOx emissions standards.
Read More →
Alt-Fuel Moves: EV Charging & Infrastructure Projects Gain Momentum
The latest developments include new funding, charging infrastructure, utility investments, and fleet technologies designed to support the transition to electric school buses nationwide.
Read More →
Alt-Fuel Moves: Fleets Power Up Beyond the Bus
See how districts are pairing electric buses with charging, solar, and V2G technology to cut costs, boost resilience, and unlock new fleet value.
Read More →
What the EPA’s Updated Clean School Bus Program Means for Fleet Electrification in 2026 and Beyond
A guide to the EPA’s evolving school bus grants, including how the Trump administration changed funding priorities and how school districts can prepare for future bus purchases.
Read More →
