Processing categories: area, mobile, point
An emission inventory is built and reported for a variety of compounds or chemical classes such as CO, NOx, VOC, PM10, and SO2. However, AQM photochemical mechanisms (e.g., CB4, RADM2) contain a simplified set of equations that use representative “model species” to represent atmospheric chemistry. Therefore, source-specific factors are needed to convert the emissions from the chemical classes in the emission inventory to the species in the intended photochemical mechanism. The Spcmat program produces matrices that contain the factors for performing this conversion.
Spcmat outputs both mass-based and mole-based factors for all sources. Previous systems have assumed that the average molecular weight of the model species was sufficient to represent the molecular weight of a species emitted by a specific source. In fact, the actual molecular weight of a model species is different for different types of emission processes. To represent the mass values more accurately, the mass and mole factors are computed and stored separately.
The speciation cross-reference file input to Spcmat specifies the speciation profile to be used for transforming the inventory pollutants to the model species for each source or type of source. Spcmat permits profiles to be assigned based on the country, state, and county code, the SCC, and other source characteristics. In the hierarchical system used to apply the profiles, the most specific assignments are applied first, followed by the next most specific, and so on. This system ensures that the most-specific matches override the less-specific ones.
For stationary area/nonpoint sources, the available combinations and their order are the following, starting with the most specific. “Left x of SCC” refers to an 8- or 10-digit SCC with all digits except the first x set to 0. “Left 2 of SIC code” refers to a 4-digit SIC code with the third and fourth digits set to 0.
Country/state/county code, MACT code, and 8- or 10-digit SCC
Country/state/county code and MACT code
Country/state code, MACT code, and 8- or 10-digit SCC
Country/state code and MACT code
MACT code and 8- or 10-digit SCC
MACT code
Country/state/county code and 4-digit SIC code
Country/state/county code and left 2 of SIC code
Country/state code and 4-digit SIC code
Country/state code and left 2 of SIC code
4-digit SIC code
Left 2 of SIC code
Country/state/county code and 8- or 10-digit SCC
Country/state/county code and left 6 or left 7 of SCC
Country/state code and 8- or 10-digit SCC
Country/state code and left 6 or left 7 of SCC
8- or 10-digit SCC
Left 6 or left 7 of SCC
Country/state/county code
Country/state code
Ultimate default (country/state/county code = 0, SCC = 0)
For nonroad sources, the available combinations and their order are:
Country/state/county code and 10-digit SCC
Country/state/county code and left 7 of SCC
Country/state code and 10-digit SCC
Country/state code and left 7 of SCC
10-digit SCC
Left 7 of SCC
Country/state/county code
Country/state code
Ultimate default (country/state/county code = 0, SCC = 0)
For mobile sources, the available combinations and their order are:
Country/state/county code, road class, vehicle type, and process
Country/state/county code, road class, and vehicle type
Country/state/county code, road class, and process
Country/state/county code and road class
Country/state/county code, vehicle type, and process
Country/state/county code and vehicle type
Country/state code, road class, vehicle type, and process
Country/state code, road class, and vehicle type
Country/state code and road class
Country/state code, vehicle type, and process
Country/state code and vehicle type
Road class, vehicle type, and process
Road class and vehicle type
Road class
Vehicle type and process
Vehicle type
Country/state/county code and process
Country/state/county code
Country/state code and process
Country/state/county code
Process-specific ultimate default (country/state/county code = 0, SCC = 0)
Ultimate default (no process, country/state/county code = 0, SCC = 0)
For point sources, the available combinations depend on the source definition. A header in the speciation cross-reference file format allows you to indicate the source definition. (The header is required for IDA inventories). For IDA-formatted inventories, a source is defined as the unique combination of country/state/county code, plant ID, point ID, stack ID, segment, and SCC. For point sources, the available combinations and their order are:
Country/state/county code, plant ID, point ID, stack ID, segment ID, and SCC
Country/state/county code, plant ID, point ID, stack ID, and segment ID
Country/state/county code, plant ID, point ID, and stack ID
Country/state/county code, plant ID, and point ID
Country/state/county code and plant ID
Country/state/county code, MACT code, and SCC
Country/state/county code and MACT code
Country/state code, MACT code, and SCC
Country/state code and MACT code
MACT code and SCC
MACT code
Country/state/county code and 4-digit SIC code
Country/state/county code and left 2 of SIC code
Country/state code and 4-digit SIC code
Country/state code and left 2 of SIC code
4-digit SIC code
Left 2 of SIC code
Country/state/county code and SCC
Country/state/county code and left 6 of SCC
Country/state/county code and left 3 of SCC
Country/state/county code and left 1 of SCC
Country/state code and SCC
Country/state code and left 6 of SCC
Country/state code and left 3 of SCC
Country/state code and left 1 of SCC
SCC
Left 6 of SCC
Left 3 of SCC
Left 1 of SCC
Country/state/county code
Country/state code
Ultimate default (country/state/county code = 0, SCC = 0)