New low- or no-emission vehicles purchased partly from a national settlement against Volkswagen for rigging pollution-control equipment on diesel cars will hit central Ohio streets this summer.

Ohio's share of the settlement is $75.3 million.

Columbus City Schools, Ohio State University, the Central Ohio Transit Authority and Big Walnut Local Schools all took different approaches to the problem of reducing emissions, but all share a common goal: to remove nitrogen oxide, which causes smog and acid rain, from central Ohio air.

Leading the pack is Columbus City Schools, which is awaiting the shipment of 40 new diesel buses that "meet the highest emission standards with Cummins engines and achieve EPA goals of improved air quality," according to the purchase resolution approved by the school board last month.

Half of the nearly $4 million expense was paid out of the settlement fund. New buses should arrive in July, replacing ones built in 1991, district spokesman Scott Varner said. All vehicles being replaced under the program must be scrapped rather than resold.

The new buses will emit 9.7 fewer tons of nitrogen oxide each year than the current ones, according to Ohio Environmental Protection Agency documents.

Ohio State will retire six 2002 diesel buses and replace them with compressed-natural-gas buses.

The CNG buses will arrive in July, with the settlement fund paying half of the roughly $3 million cost. The CNG buses will emit 4.5 fewer tons of nitrogen oxide per year than the current ones, according to the state EPA.

When the buses are delivered, Ohio State will have 22 CNG buses, comprising about half its fleet. They will fuel up at a CNG station installed a few years ago on campus, said Beth Snoke, director of transportation and traffic management for the university. Natural-gas buses cost less to operate: the equivalent of 90 cents per gallon compared to $2.68 per gallon for diesel, Snoke said.

The purchase is part of the university's goal to reduce its carbon footprint by 25% by 2025, she said.

"We're committed to compressed natural gas," Snoke said. "It's a resource that we have readily available."

COTA is taking a different tack, using the grant to purchase five all-electric, rechargeable buses, "going toward our effort to get diesel-free within five years," spokesman Jeff Pullin said. COTA is the only transit authority of the four to use its grant money for all-electric buses.

Because COTA still must build a charging station, the buses won't be purchased until late next year, Pullin said. The grant will pay about $1 million, or 30% of the cost. The project will remove 1.3 tons of nitrogen oxide per year.

The Big Walnut Local Schools in Delaware County received $138,000 for half the cost of three new propane-powered buses, replacing diesels. When they are delivered in August, 19 of the district's 36 buses will run on propane. Natural gas wasn't an option because of the cost of locating a fueling station, said Ron McClure, Big Walnut's director of administrative services.

Past carburetor problems with older propane vehicles have been worked out, and maintenance costs are now lower than with diesels, McClure said.

The district saves about $1 a gallon using propane instead of diesel fuel, he said.

The purchases were part of a $15 million first round of state grants that eventually will total more than $70 million. The next round of applications will begin in June.

After all the money is allocated, $30 million will have gone to school districts and transit authorities, said Anthony Chenault, Ohio EPA spokesman.

The rest of the money will go toward replacing public and private trucks and shuttle buses ($10 million); tugboats and ferries ($2 million); switchyard locomotives ($5 million); airport cargo-handling vehicles ($12 million); and the equipment needed to recharge personal electric and hydrogen fuel-cell vehicles ($11.25 million), according to the Ohio EPA plan.

The Ohio EPA decided that private businesses also would participate in the grant program, and tens of millions of dollars are expected to be awarded to companies to replace aging equipment. Private entities receiving cash in the first round included Coca-Cola Bottling Co., Kroger and United Airlines.

The Ohio EPA will retain just over $5 million, or 7%, to administer the program.

The settlement was reached after Volkswagen pleaded guilty in January 2017 to federal criminal charges and signed a statement of facts acknowledging it had installed illegal "defeat devices" on diesel cars that allowed them to emit up to 40 times the U.S. limit on nitrogen oxide emissions.

Volkswagen software in the cars could detect when they were hooked up to a pollution-testing device, thereby shifting the engine into a lower-emitting setting. Once out of the test station, the Volkswagens were designed to go back to normal operation, allowing higher performance – and more pollution.

"Reducing emissions from diesel engines is one of the most important air-quality challenges facing Ohio," the Ohio EPA mitigation plan said. The total amount of nitrogen oxide released by on- and off-road diesel vehicles in Ohio in 2014 alone was 106,000 tons.

bbush@dispatch.com

@ReporterBush