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Nonroad Engine Population Estimates

Abstract

The purpose of this memorandum is to document the source of the nonroad engine population values used in EPA’s final NONROAD2008a emission inventory model. Engine populations are provided as default values in EPA’s NONROAD emission inventory model categorized by equipment type, power level, and fuel type. This categorization allows the NONROAD model to determine the phase-in of new emission standards and other unique aspects of emissions or allocations by application, fuel type, or power level. Relative to the previous December 2005 version of this report, this version includes population estimates for high performance sterndrive and inboard (SD/I) recreational marine engines.