U.S. Environmental Protection Agency
Office of Mobile Sources
June 19, 1998


                     NONROAD Release Notes
  Weaknesses, Special Features, or Other Valuable Information

Error Checking

          The interface currently lacks an error checking feature to
     alert the user that illogical values or values that are
     beyond the limits of the model were entered to define a
     modeling scenario, e.g., minimum temperature is greater than
     maximum temperature or a fuel sulfur content greater than
     0.5 wt %.  Therefore, care should be taken in entering
     values in the interface.  This feature will be added to the
     final model.  On the other hand, the core model has an error
     checking feature.  Egregious errors, which "crash" the
     model, will cause a message display in the DOS window.  Less
     offensive errors will be noted in the output .msg file.

Bad Results

          Seasonal or Daily U.S. Total Scenarios - The draft model
     does not properly calculate nationwide  inventories
     (U.S.Total) for seasonal, monthly, or daily periods.
     Suitable allocation indicators for these time periods have
     not been developed.  However, the model does properly
     calculate annual (yearly) nationwide inventories. 
     Therefore, only the latter nationwide period should be
     modeled at this time.
  
          State and County Allocations for Some Equipment Categories -
     Allocation indicators used for recreational (public golf
     course employees for golf carts and number of RV Parks for
     all other recreational equipment), railroad maintenance
     (human population), underground mining (metals mining),
     AC/refrigeration equipment (human population) are
     placeholders. EPA has not yet found adequate indicators for
     these categories and encourages suggestions in this area
     during the public comment period.

Interim Results

          Refueling Methodology - The refueling methodology used in
     the draft version of NONROAD is oversimplified and does not
     reflect the impact of user-specified temperature and RVP on
     refueling emissions. In addition, EPA is still reviewing
     available information on tank volumes. As a result,
     refueling emissions from the draft model should be viewed
     with extra caution.
     
          Aircraft GSE Methodology - EPA anticipates revising the
     aircraft ground support equipment (GSE) methodology to be
     consistent with other inventory assessment tools such as the
     ARB OFFROAD model and the FAA EDMS model. This method is based
     on an estimate of GSE use per aircraft landing and takeoff
     cycle.
                    
No Results

          Snowmobiles and snowblowers - The model currently reports
     nationwide (U.S. Total) values for snowmobiles and
     snowblowers. It outputs "0" values for state or county
     regions, since adequate allocation indicators for these source
     categories have not yet been identified. 

Rail Equipment Clarification 

          This category includes various railway maintenance equipment.
     It excludes locomotive engines. This latter category will be
     added to the model sometime in the future as described below. 

Excluded Equipment Types

          Commercial Marine - EPA is currently developing the
     programming code and data inputs for estimating commercial
     marine emissions. This work is expected to be complete in late
     August or early September. At that time, a draft model
     containing the commercial marine category will be released for
     public comment.

          Locomotives and Aircraft - The model currently excludes
     locomotives and aircraft. The final version of NONROAD will
     also exclude these equipment types. These categories will be
     included in future updates of the model. Nonetheless, EPA
     plans to update the existing guidance for locomotives and
     aircraft in written or other electronic form within the next
     year.

Technical Reports

          Several technical reports have been updated to reflect new
     information or public comments. These reports cover equipment
     populations (NR005a); median life, activity, load factor
     (NR006a); CI emission factors (NR009a); and SI emission
     factors (NR0010a). The information in these revised reports
     has been incorporated in the draft model.

Important Addresses and Numbers

          Questions or comments may be sent electronically to the
     NONROAD mailbox at nonroad@epa.gov.  You may also send this
     information to the EPA contact person, Gertrude Venlet, at
     U.S. EPA, Office of Mobile Sources, Assessment and Modeling
     Division, Scientific Assessment Group, 2000 Traverwood Drive,
     Ann Arbor MI 48105.  If you require more immediate assistance
     with the model, please call Ms. Venlet at(734) 214-4892.

Check the Web Site Frequently

          Please check our web site often for additional technical
     reports and other new information.  You may also want to
     subscribe to the MOBILE listserver, if you have not already
     done so, to automatically receive future announcements
     regarding NONROAD (instructions can be found on the web page
     -- http://www.epa.gov/omswww/nonrdmdl.htm). 
