A switch to electric buses at the MBTA could avert greenhouse gas emissions in an amount equivalent to taking 10,631 cars off the road, according to a new report.

Released Thursday by MASSPIRG, the report, titled "Electric Buses: Clean Transportation for Healthier Neighborhoods and Cleaner Air," looks at potential health, environmental and financial benefits of transitioning to all-electric bus fleets.

About 95 percent of the nation's school buses and more than 60 percent of transit buses run on diesel, according to the report, which also said 18 percent of the nearly 70,000 transit buses in the country run on natural gas and 0.2 percent are all-electric.

"Diesel exhaust from buses poses a particular risk to health," the report said. "Buses primarily travel where there are lots of people, including in the more densely-crowded areas of cities, on the busiest roads, and near schools. They also circulate continuously and make many trips, and therefore risk exposing many people to emissions. The good news is that America can clean up its buses by making them electric."

While the switchover would involve major new expenses, MASSPIRG estimates that replacing all of America's school buses with electric models could avoid an average of 5.3 million tons of greenhouse gas emissions each year, and each electric school bus could save districts nearly $2,000 a year in fuel and $4,400 in reduced maintenance costs.

In May 2016, the state Department of Energy Resources awarded four school districts — Amherst, Cambridge, Concord and Acton-Boxborough Regional — grants of up to $350,000 each to buy electric school buses and chargers, as part of a pilot program aimed at reducing schools' petroleum use and testing the benefits of electric school buses.

The department said the program was "one of the first demonstrations of electric school bus technology on the East Coast of the United States."

On the transit side, a transition to all-electric buses at the MBTA could avoid an annual 55,071 tons of greenhouse gas emissions, the report found.

The study cites prices from two bus manufacturers. At New Flyer, natural gas powered buses start at $450,000 while electric versions start at $700,000, and Proterra's standard electric transit bus costs $750,000 compared to $500,000 for a conventional diesel bus.

"Even though electric buses today are still more expensive upfront than their diesel or natural gas-powered counterparts, electric transit buses can pay for themselves within 10 years of operation through fuel savings and reduced maintenance costs," the report said.

The report notes that transit agencies can receive federal assistance for capital costs like purchasing buses, but not for operating costs, and said increases in the ranges of electric buses make them an "increasingly feasible option."

To fund the purchase of electric buses, the report recommends using money from the 2016 settlement with Volkswagen over the auto company's violation of clean air standards or participating in federal programs like the U.S. Department of Transportation's Low or No Emission Vehicle grants.

Utility companies could also "play a major role," by investing in charging infrastructure along bus routes or developing rate structures that make electric bus charging more economical, the report said.