For point, nonpoint, on-road mobile, and nonroad-mobile sources, the toxics inventory contains emissions for VOC pollutants that are provided as explicit chemical compounds (for example, benzene). These same VOC emissions are also included as an aggregated VOC value in the criteria emissions inventory. To use these inventories together, Smkinven provides the necessary options to ensure that double counting of VOC emissions will not occur. These two options are the “integrate” and “no-integrate” options.

The “integrate” option involves subtracting toxic VOC emissions from the criteria VOC emissions to avoid double counting of VOC when the emissions are speciated. With this option the user must ensure that the sources in the toxics and criteria inventories match up one-to-one, so that Smkinven can properly compute the emissions.

Note that in any discussion of the toxics inventory we have assumed that all emissions are annual total emissions, because the toxics inventory that is currently available does not include average-day emissions. We have also assumed that the inventory contains VOC emissions, but the same approach can be used to process TOG emissions.

During import of both toxics and criteria emission inventories, SMOKE matches the area/nonpoint, on-road mobile, and nonroad mobile emission inventories by country/state/county code and SCC. SMOKE also matches the toxics and criteria records for the point sources, provided that the point sources in the two inventories use identical fields for their source characteristics. You are required to ensure that the source characteristics for all source categories match between the two inventories for any sources that you wish to have matched. Once they are matched, SMOKE will have both a criteria VOC emissions value and toxics emission values for individual VOC chemical compounds.

SMOKE can optionally compute a NONHAPVOC value by subtracting the sum of toxics VOC from the criteria VOC value. This same approach can be used to create a NONHAPTOG value if the inventory or MOVES (when processing on-road mobile emissions using VMT data) uses a TOG value instead of a VOC value. (We will not mention NONHAPTOG again, but it could be used to replace NONHAPVOC throughout this section).

The case of computing NONHAPVOC is called the “integrate” case because it involves integration of the VOC mass between the criteria and toxics inventories. Likewise, the case of not computing NONHAPVOC is called the “no-integrate” case. With the “integrate” approach, the NONHAPVOC mass and the toxics VOC mass are independent from one another and will not double count emissions. The calculation must be performed for each source, and Smkinven will set the criteria VOC value to zero when it computes the NONHAPVOC value. Smkinven determines which pollutants should be subtracted from VOC using the “VOC or TOG” column in the inventory table (INVTABLE) file.