SMOKE processes criteria, particulate, toxics, and activity data inventories. Activity data will be discussed along with on-road mobile sources in the next section. By criteria inventories, we mean inventories containing EPA’s criteria pollutants: carbon monoxide (CO), nitrogen oxides (NO_x), and volatile organic compounds (VOC) or total organic gases (TOG). Particulate inventories contain ammonia (NH₃), sulfur dioxide (SO₂), particulate matter (PM) of size 10 microns or less (PM₁₀), and PM of size 2.5 microns or less (PM_2.5).

Additionally, SMOKE can process inventories with pre-speciated criteria and/or particulate emissions. For example, elemental carbon of size 2.5 microns or less can be provided as input to SMOKE directly, instead of letting SMOKE’s speciation step compute it from the PM_2.5 total emissions. To ensure that SMOKE correctly processes the data when you are using pre-speciated emissions, other input files must be configured in specific ways, as explained in Section 4.5.10, “Use a different speciation mechanism or change speciation inputs”.

The toxics inventories that SMOKE can process are data from the National Emission Inventory (NEI) for Hazardous Air Pollutants (HAPs). This inventory contains hundreds of specific compounds representing the 188 HAPs defined by the Clear Air Act. The original list of 189 HAPs and modifications representing the current list are available from the EPA’s web site. The reason the inventory contains many more pollutants than 188 is because several on the list of 188 are pollutant groups, such as polycyclic organic matter, cyanide compounds and numerous metal compounds including chromium compounds, cadmium compounds, manganese compounds, and others. Note that because of these groups, specific compounds in the inventory in one inventory year may not exactly match the compounds in another inventory year. For example, one may have lead oxide reported one year but not in a subsequent year. However, those compounds not belonging to compound groups are likely to be in the inventory year after year, particularly the common gaseous HAPs emitted by mobile sources such as benzene, 1,3-butadiene, acrolein, formaldehyde, and acetaldehyde.

In the default configuration of SMOKE described in Chapter 3, SMOKE Directories and Default Data, a particular list of HAPs based on the draft 1999 NEI for HAPs (October 2002) was used to set up the INVTABLE ancillary file. It is important to understand that you may need to modify the default configuration to accommodate the particular toxics inventory you are inputting into SMOKE. For example, if you have cadmium chloride in your inventory, which was not in the draft 1999 NEI for HAPs, then you would need to add this pollutant to the INVTABLE. See Section 4.5, “How to use SMOKE” for more details about making such changes. In addition, note that in the default configuration, not all of these pollutants are actually used because the CMAQ and REMSAD models (the two toxics models that SMOKE supports by default) do not use them all. In fact, most of the metal pollutant groups on the list of HAPs (lead compounds, cobalt compounds, manganese compounds, beryllium compounds, chromium compounds, and others) are not currently supported by the grid models.