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June 2007

Summary of NMIM Issues and Bugs
January 2006 - June 2007

Below is a summary of NMIM issues, bugs, and suggested approaches to addressing these problems which have been identified by EPA since NMIM was released in December 2005.

Jan/Feb 2006

EPA Announces Potential Problems Running NMIM2005 and NONROAD2005. EPA released NONROAD2005 and NMIM2005 on December 7, 2005. On December 19, December 20, December 21, 2005 and January 6, January 31 and February 9, 2006 EPA issued a number of corrections to running these models. The NMIM2005 installation instructions were updated on December 19 and 20, NONROAD2005 Reporting Utility Problems and Corrections were announced on December 21, on January 6 several problems with NMIM2005 instructions were identified, and on January 31 and February 9 additional minor corrections to NONROAD2005 and NMIM2005 were announced. All updates are available for download from the NONROAD model web site at: http://www.epa.gov/otaq/nonrdmdl.htm. For more information, contact "Dave Brzezinski" at mobile@epamail.gov. To join in the list serve see: http://www.epa.gov/oms/models/mobillst.txt.

June 2006

EPA Announces Two New NMIM Problems. On June 13, 2006 EPA announced two problems with the NMIM2005 that users may encounter which have not been previously described. The first is a code error affecting NMIM's Nonroad User-Specified Fleet function. The second is an error in the SCC Table of the NMIM County Database (NCD) affecting PM2.5 from nonroad diesel engines. As soon as possible, EPA will post full descriptions and workarounds as well as EPA's plans to provide fixes on its website at: http://www.epa.gov/otaq/nmim.htm.

November 2006

Errors in NMIM Files. On November 15, 2006 EPA announced errors in the NMIM County Database NCD20060201. These files specify the years that various NLEV standards apply. The errors affect NOx and VOC emissions from on-road light-duty gasoline vehicles in six states for inventories generated for calendar years 2004 or later. The states are Connecticut, Maine, New Hampshire, New Jersey, Pennsylvania and Vermont. The errors in these files result in over estimation of NOx and VOC emissions from light duty gasoline vehicles in 2004 and subsequent years. The over estimation is close to 2004, but becomes progressively greater in later years as the fleet turns over. Only NMIM runs for calendar years 2004 and later for the states listed above are affected by this error. EPA plans to distribute a revised database with corrected versions of these files. If you have any questions, please email EPA at mobile@epa.gov.

January 2007

NMIM Bug - Nonroad Diesel Retrofits and Gasoline Evaporative Emissions. EPA identified a problem modeling any fleet-wide nonroad diesel program in NMIM2005 in the same model run where you have nonroad gasoline-fueled equipment. EPA's work around suggestion is to always do a separate model run for nonroad spark-ignition (gasoline, LPG, CNG) equipment versus nonroad diesel equipment whenever your NMIM model run includes any nonroad diesel retrofit program without use of a nonroad fleet information file. If you have any questions, please email to: mobile@epa.gov.

April 2007

NMIM Update: Nonroad Diesel Retrofits Affect Gasoline Engine Evaporative Emissions.On April 2, 2007 EPA announced that some potentially important information is missing from the NONROAD2005 User Guide regarding the use and limitations of the Daily Temperature & RVP input data file. This relates to EPA's NMIM model because NMIM is not designed to make use of the Daily Temperature & RVP feature of the NONROAD model. NMIM inherently runs NONROAD on a monthly basis and applies the temperatures and fuel properties (such as RVP) by county from the NMIM County Database. More information can be found at: http://www.epa.gov/otaq/nonrdmdl.htm.

June 2007

Errors in NMIM Files.On November 15, 2006 EPA announced errors in the NMIM County Database NCD20060201. These files specify the years that various NLEV standards apply. The errors affect NOx and VOC emissions from on-road light-duty gasoline vehicles in six states for inventories generated for calendar years 2004 or later. The states are Connecticut, Maine, New Hampshire, New Jersey, Pennsylvania and Vermont. The errors in these files result in over estimation of NOx and VOC emissions from light duty gasoline vehicles in 2004 and subsequent years. The over estimation is close to 2004, but becomes progressively greater in later years as the fleet turns over. Only NMIM runs for calendar years 2004 and later for the states listed above are affected by this error. EPA plans to distribute a revised database with corrected versions of these files. If you have any questions, please email EPA at mobile@epa.gov.

January 2007

NMIM Bug - Nonroad Diesel Retrofits and Gasoline Evaporative Emissions. EPA identified a problem modeling any fleet-wide nonroad diesel program in NMIM2005 in the same model run where you have nonroad gasoline-fueled equipment. EPA's work around suggestion is to always do a separate model run for nonroad spark-ignition (gasoline, LPG, CNG) equipment versus nonroad diesel equipment whenever your NMIM model run includes any nonroad diesel retrofit program without use of a nonroad fleet information file. If you have any questions, please email to: mobile@epa.gov

April 2007

NMIM Update: Nonroad Diesel Retrofits Affect Gasoline Engine Evaporative Emissions.On April 2, 2007 EPA announced that some potentially important information is missing from the NONROAD2005 User Guide regarding the use and limitations of the Daily Temperature & RVP input data file. This relates to EPA's NMIM model because NMIM is not designed to make use of the Daily Temperature & RVP feature of the NONROAD model. NMIM inherently runs NONROAD on a monthly basis and applies the temperatures and fuel properties (such as RVP) by county from the NMIM County Database. More information can be found at: http://www.epa.gov/otaq/nonrdmdl.htm.

June 2007

EPA Announces Bug in NMIM NONROAD Fleet Function. On June 5 EPA issued a notice on a NMIM nonroad fleet function bug and a work-around to this problem. This bug occurs only if a numeric activity (hours/year) is specified in the Fleet Information File (FIF). The work-around for this problem is to ignore all monthly emissions which have an allocation of zero in the FIF. Alternatively, do not select any months in the NMIM "Time" panel for which monthly allocations in the FIF are zero. Questions or comments regarding NMIM should be emailed to: mobile@epa.gov.

Updated: 07/06/2011
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