Question about S2S-TOOL for CRACMM2

CMAQ Chemistry and Aerosols
,
1

I want to run the mech of CRACMM2, and I need to build the species of CRACMM2. I have read the user guide, and I have some questions.

  1. I have the VOC and PM2.5 species of BC06_AE6 mechanism, can I use S2S-TOOL to map the species composition of CRACMM1 mechanism?

2.There are many input files in S2S-TOOL, should I enter the composition in the export_species.csv file? I define PROFILE_CODE myself, query SPECIES_ID, and fill in WEIGHT_PERCENT?

3.The mechanism_forImport_SPECIATEv5_3.csv file has several different Moles of the same species in the same chemical mechanism, how should I choose?
Thanks for your help, especially @Havala.Pye.
Best
pbwang

2

Hello pbwang,
The overall process for creating emissions (following EPA methods) involves:

  1. Information about how inventoried pollutants are speciated into individual compounds. These are generally profiles for how total VOC (or NMOG) is speciated into benzene, toluene, decane, formaldehyde, … and PM2.5 into sulfate, OC, nitrate, … We use profiles in the SPECIATE database. These are not mechanism specific.
  2. S2S-Tool maps the speciation profiles from (1) to a mechanism. SPECIATE (the export_species.csv file, see User guide) is an input to S2S-Tool. S2S-Tool outputs gspro, gscnv, etc files that will describe how VOC from a given source is split into BEN, TOL, HC10, etc and how PM2.5 is split into PMSO4, AROCP1ALK, etc. The output of S2S-Tool will be mechanism specific. S2S-Tool can run for any mechanism.
  3. The speciation profiles from (2) are combined with emission abundances, typically in the SMOKE tool. SMOKE uses the gspro, gscnv, etc with inventory abundances to generate gridded, CMAQ model-ready, mechanism-specific information.

It sounds like you have already completed these steps for CB6. Mapping model-ready emissions in CB6 to CRACMM directly (e.g. via combine or via DESID control files) is not recommended without some additional information due to the differences in lumping in the two mechanisms. Mapping directly from CB6 to CRACMM is OK for boundary and initial conditions as the boundaries are more chemically processed (species are more similar across mechanisms as some of the emitted nuance has reacted away) and initial condition effects can be removed through spinup.

S2S-Tool has already been run for CRACMM. You can find the gspro output as well as other inputs for SMOKE for CRACMM2 as part of the EPA 2022v1 emission platform here: https://gaftp.epa.gov/Air/emismod/2022/v1/for_CRACMM/.

Havala