High school senior Anika Gupta has always ridden the bus to school, but a trip she took last month in northern Virginia was different. Not only was EPA Administrator Michael Regan along for the ride, but the bus was electric.

Regan spoke with Gupta, 17, and a few other students about his agency’s new program to electrify school buses across the country.

“It was a great ride,” Gupta said. Better than the diesel-powered vehicles she’s used to, where “the bus smell is very strong, especially after school when all the buses are parked in front of the school and everyone goes and finds their bus and it just smells like gas.”

That odor could be harming Gupta and her fellow students. Diesel exhaust has been classified as a human carcinogen, and it can lead to and exacerbate respiratory conditions. Those health conditions are exactly what EPA’s new Clean School Bus program aims to address.

“Transitioning to a clean transportation future means cleaner air and less pollution,” Regan said during the event. “It means healthier kids and a greater focus and productivity.”

Transportation is the single-largest source of greenhouse gas emission in the United States. And while diesel-powered vehicles are a small fraction of the country’s fleet, they spew the vast majority of planet-warming emissions and harmful air pollution, such as nitrogen oxide and particulate matter.