Sept 15, 2004


Cautionary Note regarding NIF Output from Draft NONROAD2002a and Draft
NONROAD2004

NOTE: These issues do not affect inventories generated with NMIM,
since NMIM does not use the NONROAD Reporting Utility. 

The following issues apply to both the NIF 3 export function in
version 3.0 of the NONROAD Reporting Utility and the NIF 2 export
function in version 2.4a of the Reporting Utility (as well as the
earlier version 2.2a of the Reporting Utility that was included with
Draft NONROAD2002a). These have been distributed as part of the Draft
NONROAD2004 model at http://www.epa.gov/otaq/nonrdmdl.htm (and earlier
as part of Draft NONROAD2002a). 

1) The NIF export function of the Reporting Utility does not export EM
records for evaporative emissions that were less than 0.0001.  This
results in very small or insignificant changes in the inventories. In
the NIF 2 export function in version 2.4a of the Reporting Utility the
same issue also applies to exhaust emissions. 

2) For some as yet undetermined reason the NIF export function
sometimes multiplies the HC output by 100 for one or a few equipment
types (SCCs). The SCCs affected are not consistent. Thus we recommend
at least spot checking the NIF HC outputs by comparing the NIF HC
totals to the HC totals from the main reporting utility reports or to
the raw model outputs contained in the *.OUT files generated by the
core model. Additionally, if these totals indicate any significant
difference, then the inventory values can be compared at the SCC level
to determine where specifically the error occurred.  EPA is making
available on the NONROAD model web site a postprocessing tool to help
make direct comparisons of county/SCC aggregated emissions from the
NONROAD raw output (.OUT) files with the Reporting Utility NIF outputs. 


Questions/Problems: nonroad@epa.gov

U.S. Environmental Protection Agency
Assessment and Standards Division
Air Quality and Modeling Center
2000 Traverwood Drive
Ann Arbor, MI 48105