The Minnesota Environmental Initiative's Project Green Fleet (PGF) is an effort to protect children's health and reduce pollution by providing retrofits to Minnesota's school buses and other diesel vehicles. PGF is a voluntary partnership between government, private industry, and the non-profit sector that purchases and installs pollution-control equipment at no cost to participating school bus fleets. PGF helps Minnesota address air quality problems before they become more serious environmental and health threats.

PGF is working to complete the retrofit of all 4,000 eligible school buses in the state. PGF also aims to reduce Minnesota's ambient air pollution, and help Minnesota avoid being declared a non-attainment area under the federal Clean Air Act.

Since its kick-off in 2005, PGF has retrofit more than 1650 school buses, 80 heavy-duty diesel trucks/off-road equipment, repowered dozens of heavy-duty diesel engines, and helped partners institute idle reduction policies. The project has introduced diesel emission reduction activities into numerous industry sectors and drafted the state's Diesel Emission Reduction Strategy. Since the program began, it has received more than 21 grants and donations from 11 public and private sources totaling more than $8 million for diesel emission reduction work. PGF has built a national and state award-winning, informed, effective, and capable infrastructure of partners and vendors around diesel emission reduction efforts.