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Emissions Modeling Clearinghouse
Speciation
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Another step in modeling inventory development is speciation. This is the process of disaggregating inventory pollutants into individual chemical species components or groups of species. The need for speciation is determined by the inventory purpose. Inventory applications that require detailed speciation include photochemical modeling, air toxics inventories, chemical mass balance modeling, and visibility modeling. Depending on the purpose of a particular emissions inventory, the inventory may include TOG, NOx, sulfur oxides (SOx), CO, total suspended particulate matter (TSP), particulate matter less than 10 micrometers in aerodynamic diameter (PM10), or ammonia (NH3). However, modeling inventories may require these emissions to be expressed in terms of other pollutants. Additionally, for some models, NOx emissions may need to be specified as NO and NO2. Also, PM may need to be separated into various fractions, such as PM10 and PM less than 2.5 micrometers in aerodynamic diameter (PM2.5). |
| Related Tables and Speciation Sites |
| Speciation
Profile Usage Memorandum (3/8/2002) This document describes the usage of the profile assignment, TOG conversion, and CBIV profile files. |
(PDF 19K) |
| Source
Category Code / Speciation Profile X-Reference File (3/8/2002) This file identifies both the PM and organic gases profile codes that EPA uses for each SCC. |
(XLS 1M) |
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VOC/ROG to TOG Conversion Ratios File (4/23/2003)) This file provides the augmentation ratios, by SCC, to create the "TOG" emissions needed by the organic profiles. |
(XLS 270K) |
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Carbon Bond IV & PM Profiles File (3/8/2002) This file provides the molar split factors and mass fractions used to create CBIV lumped species and PM species from TOG and PM2.5 inventories. |
(XLS 201K) |
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Titles and Documentation for PM Profiles (4/26/2005) |
(XLS 30K) |
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Recommendations for the Update of PM2.5 Split Factors (9/29/2003) |
(PDF 240K) |
| SPECIATE:
User-friendly interface for viewing individual organic compound profiles (not lumped modeling species) used to create the CBIV profiles. |
Carbon
Bond IV  The Carbon Bond-IV Mechanism was developed mainly for urban smog and regional atmospheric modeling. |