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Emissions Modeling Clearinghouse
EMS-HAP Model Version 3 Emission Reduction & Growth Factor Ancillary Files

May 2005

We are providing, for your review and comment, a set of emission reduction and growth factor ancillary files for use with EMS-HAP Version 3.0 for hazardous air pollutant (HAP) emission projections. We also describe (in the README files) how we developed these files and how EMS-HAP uses them for projecting future year emissions from a baseline emission inventory. EMS-HAP version 2.0 is an emissions model that prepares annual toxics emission inventory data, such as the 1996 NTI, for subsequent air quality modeling using either the ASPEN or ISCST3 model. EMS-HAP can also project emissions to a future year, if you provide the emission reduction and growth factor ancillary files.

The emission reduction and growth factor ancillary files we are providing are tailored to the use of the 1999 National Emission Inventory (NEI) for HAPs (7/03 version) as the baseline inventory. The emission reduction and growth factor files can be used to project the stationary source emissions in this inventory to 2002 through 2010, 2015 and 2020. We also describe how we created these files (in the README files). The methodology used by EMS-HAP to apply the emission reduction and growth factor values to a baseline inventory for estimating future-year emissions is summarized in the README files and is described in greater detail in the EMS-HAP user's guide (see Chapters 6 and 9). In general the following calculation is done for each record in the inventory:

Future year emissions = baseline emissions * growth factor * (100 - percent reduction)/100

BACKGROUND

EMS-HAP version 3.0 is an emissions model that prepares annual emission inventory data for subsequent air quality modeling using either the ASPEN or ISCST3 model. The key functions it performs to prepare the inventory for these air quality models are: spatial allocation of county-level data to tracts or 1 by 1 km grids, temporal allocation of annual emissions to hourly rates, grouping and selection of inventory species into ASPEN or ISCST3 modeled species, and creation of properly formatted input files. EMS-HAP version 3.0 can also project an inventory to a future year by applying reductions based on rules developed as part of the Clean Air Act or user defined reductions, and by applying economic growth factors based on the emissions source type. The reduction information and growth factors are supplied to EMS-HAP as ancillary input files. We are providing, with the EMS-HAP code, a set of reduction files that account for the toxic reductions achieved by numerous national rules (e.g., Maximum Achievable Control Technology standards) and a set of growth factor files that allow you to estimate the impact of economic /population growth on emissions on 1999 emissions.

With regards to the projection capability of EMS-HAP and accompanying emission reduction and growth ancillary files that can support a projection of a 1999 inventory, please note the following:

1) These files apply only to the 1999 NEI (7/03 version). For more information on emission inventories, see the National Emission Inventory Data web page. Any other version of the inventory would require the revision of the files and an evaluation of the results.

2) There are several limitations with the 1999 NEI (7/03 version) and its use in subsequent air quality modeling activities. These are discussed in http://www.epa.gov/ttn/chief/net/1999inventory.html. In addition, there are limitations in performing toxics emission projections using toxics inventories.

3) The emission reduction information in the files posted here do not include reductions that will be achieved by: State/local control programs; area source rules resulting from additional source categories listed in the Urban Air Toxics Strategy the residual risk program; community-scale assessments. It also does not include mercury. Information on these additional control programs will be especially needed to project toxics emissions to years later than 2007 when many of these programs will be taking effect. You can account for these and other facility-specific reduction information in your projection by using the user-defined emission reduction option in EMS-HAP, and including user control information that you gather from these programs.

REDUCTION INFORMATION

The README_reductions file (PDF 65K) describes the emission reduction information files provided below and details how we created them.
User-friendly Excel files discussed in the readme file:
MACT_GEN.xls (XLS 400K)
MACT_SPEC.xls (XLS 460K)
EGU_coal_projection.xls (XLS 460K)

EMS-HAP - ready ancillary text files that contain emission reduction information: (EPA FTP Site. This site is not password protected.)
MACT_gen_PROJ_XXXX, where XXXX=2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2015, 2020
MACT_spec_PROJ_XXXX, where XXXX=2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2015, 2020
USER_PROJ_XXXX_cp, where XXXX=2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2015, 2020

GROWTH INFORMATION

The README_growth file describes the growth factor information files provided below and details how we created them.

User-friendly Excel file discussed in the readme file:
MACT_growth (XLS 56K)

EMS-HAP - ready ancillary text files that contain growth information: (EPA FTP Site. This site is not password protected.)
gf99mact_cp_XX, where XX = 02, 03, 04, 05, 06, 07, 08, 09, 10, 15 and 20
gfscc_XX, where XX = 02, 03, 04, 05, 06, 07, 08, 09, 10, 15 and 20
gfscca_XX where XX = 02, 03, 04, 05, 06, 07, 08, 09, 10, 15 and 20
gfsic_XX where XX = 02, 03, 04, 05, 06, 07, 08, 09, 10, 15 and 20

| Office of Air Quality Planning & Standards | Technology Transfer Network |
| Clearinghouse for Inventories & Emissions Factors |


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