The U.S. EPA is now soliciting proposals for the 2013 National Clean Diesel Funding Program.

The program, funded by the Diesel Emissions Reduction Act (DERA), provides grants to retrofit or replace older diesel vehicles to reduce emissions. School buses are among the eligible types of vehicles.

Approximately $9 million is available for this round of DERA funding.

“The DERA program has significantly improved air quality and provided critical health benefits by reducing air pollution and saving millions of gallons of fuel,” the EPA said in a statement. “EPA estimates that clean diesel funding generates up to $13 of public health benefit for every $1 spent on diesel projects.”

The agency recently issued a report to Congress that says that DERA projects from 2008 to 2010 impacted more than 50,000 older diesel engines.

The 2013 DERA request for proposals and additional information are posted here. The request for proposals will close on June 25, with funding expected to be awarded in the fall.