  SEQ CHAPTER \h \r 1 

March 12, 2007

MEMORANDUM

SUBJECT:	Comparison of Small Nonroad and Marine Spark-Ignition Emissions
to Stationary 	and Other Mobile Source Emission Inventories

FROM:        Richard S. Wilcox

	                     Assessment and Standards Division

	                     Office of Transportation and Air Quality			

TO:		    Docket EPA-HQ-OAR-2004-0008

	The purpose of this memorandum is to docket the emission inventories
for a variety of source categories that were used in the Small Nonroad
and Marine Spark-Ignition Engine Proposed Rulemaking to compare the
relative contribution of small nonroad and marine spark-ignition engines
to the emissions of other source categories.  The other source
categories include:  stationary, area, aircraft, locomotive,
diesel-fueled commercial marine vessels (Class 1 and 2), commercial
marine vessels (Class 3), small diesel marine, recreational vehicles,
large nonroad spark-ignition engines, highway vehicles, and portable
fuel containers.  The documentation consists of a Microsoft Excel
spreadsheet that contains the emission inventories from these source
categories for a number of calendar years and identifies the various
data sources (see attachment).  The pollutant species of interest are
volatile organic carbon compounds (VOC), oxides of nitrogen (NOx),
particulate matter (PM), and carbon monoxide (CO).  

	As explained in the attached Excel spreadsheet, the information for the
various source categories was taken from five EPA data sources.  

	1.	The Mobile Source Air Toxics Final Rule.  Further information on the
air toxics 			final rulemaking can be found in the docket for that rule
(EPA Docket:  EPA-HQ-			OAR-2005-0036);

	

	2.	The Regulatory Impact Analysis for the Review of the Particulate
Matter				National Ambient Air Quality Standards (EPA Docket:
EPA-HQ-OAR-2006-			0834-0048.3);

	3.	The Regulatory Impact Analysis for the Final Clean Air Interstate
Rule (EPA 			Docket: OAR-2003-0058); 

	4.	The publicly released NONROAD2005 emissions inventory model
(available at:  			  HYPERLINK "http://www.epa.gov/otaq/nonrdmdl.htm" 
http://www.epa.gov/otaq/nonrdmdl.htm .); and

	5.	The nonroad model developed for the small nonroad and marine
spark-ignition 			engine proposed rule, i.e., NONROAD2005c (EPA Docket: 
OAR-2004-0008).

Attachment

Source Selection Information – See FAR 2.101 and 3.104	Page   PAGE  2 
of   NUMPAGES  2 

