I was looking through the cmaq-12us1-cracmm2-modeling-platform-2022 data repository in the CMAS ware house (https://dataverse.unc.edu/dataset.xhtml?persistentId=doi:10.15139/S3/BDLBTW) and I noticed that the 2022 CMAQ_Control_DESID_cracmmv2.nml file has several differences compared to the default one available on the CMAQv5.5 GitHub page (both files included below). For example, the 2022 file shows a 1:1 mapping of VROC and AROC emitted species to themselves with no change in species name. In comparison, the original file has a 1:1 mapping of ROC to VROC species. What exactly are the differences between these methods?
Additionally, I noticed that the default file applies POA volatility profiles to PMN species, while the 2022 version does not (screenshots below). I know one of the main changes from cracmmv1 to cracmmv2 is that POA volatility profiles are now applied upstream and shouldn’t be applied in DESID. If using cracmmv2 speciated emissions in CMAQ, does it matter if this section is included or not? Any clarification is appreciated. Thanks!
The different DESID files correspond to different versions of emissions for use with CMAQ CRACMM2 code. The files currently in the CMAQ github repository assume CRACMM1 emissions (which use PMOCN2 and PMNCOMN2 to pass POA emissions to the model and do not prepend with A/V). The updated DESID files for 2022 are CRACMM2 emissions.
For all emissions generated by EPA, emissions labeled CRACMM1 will require the A/V and PMOCN2/NCOMN2 cross mappings to use them in CRACMM2 (or older CRACMM1). Emissions labeled CRACMM2 will have CRACMM2 model species and do not need cross mapping. The POA volatility profiles in CRACMM2 emissions can be found in the Supplement of Pye et al. 2026. CRACMM2 emissions are less error prone because mappings are all 1:1.
Unused rules can exist in your DESID file and not cause issue. We recommend the DESID emission mappings in at least one processor log are checked for any initial simulation.
In using different versions of emissions and CMAQ (e.g., CRACMM1 emissions in CRACMM2), things to watch out for are (check a processor log):
dropping of POA (CRACMM1 emissions must have rules mapping PMNCOMN2 and PMOCN2 to ROC compounds. If those emissions are not mapped, all POA will be missing.)
