U.S. Environmental Protection Agency

February, 2002

Document Released for Public Information

"Determination of Running Emissions as a Function of Mileage for 1981-1993 Model Year 
Light-Duty Cars and Trucks" 

Report Number   EPA420-R-02-002     (M6.EXH.001)
 
	The Office of Transportation and Air Quality, Assessment and 
Standards Division announces the release of "Determination of Running Emissions as 
a Function of Mileage for 1981-1993 Model Year Light-Duty Cars and Trucks" for public 
information.  This document EPA420-R-02-002, also known as M6.EXH.001, is available 
at the MOBILE6 section of the OTAQ Web Site (http://www.epa.gov/otaq/m6.htm). 

	This document describes the methodology used to calculate the in-use deterioration of 
running emissions and presents estimates for model year 1981-1993 light-duty cars and trucks 
proposed for use in MOBILE6.   It also describes the Federal Test Procedure (FTP) data sources
and the model year and technology groups used.  It also presents the methodology for calculating
running emissions from FTP bag data.  It contains a basic overview of the FTP, defines all
of the applicable emission terms, and provides the calculations for determining the base 
unit of engine running emissions.  The report describes models and results for the in-use 
deterioration of running emissions as a function of mileage. The high emitter correction
factors which are applied to the deterioration estimates are also discussed.

	This report was originally released (as a draft) in January, 2001 under the 
title, "Determination of Running Emissions as a Function of Mileage for 1981-1993 Model Year 
Light-Duty Cars and Trucks".  It was subsequently revised in February, 2002, and the 
February, 2002 is now the final version.  This final revision incorporates suggestions and 
comments received from stakeholders during the 60-day review period and from peer reviewers.