Section 1500.1 - Definitions(a)Participant support costs. The Environmental Protection Agency (EPA) has supplemented 2 CFR 200.1 , Participant support costs, to provide that allowable participant support costs under EPA assistance agreements include:(1) Rebates or other subsidies provided to program participants for purchases and installations of commercially available, standard ("off the shelf") pollution control equipment or low emission vehicles under the Diesel Emission Reduction Act program or programs authorized by EPA appropriation acts and permitted by terms specified in EPA assistance agreements or guidance, when the program participant rather than the recipient owns the equipment.(2) Subsidies, rebates, and other payments provided to program beneficiaries to encourage participation in statutorily authorized programs to encourage environmental stewardship and enable the public to participate in EPA funded research, pollution abatement, and other projects or programs to the extent permitted by statutes and terms specified in EPA assistance agreements or guidance.