How to add IVOC inventory to CMAQv5.3.2 and simulate SOA

Dear all:
In the case of not using VBS, how to add IVOC list in CMAQv5.3.2, I add different kinds of IVOC list in Emisscontrol, such as IVOA, IVOB, without using VBS mechanism, but directly simulate SOA, the result is the same as that without adding IVOC list. What is this problem? Is there a problem when setting Emisscontrol?Here is part of my Emisscontrol file.
‘EVERYWHERE’, ‘ALL’ ,‘POC’ ,‘PCVOC’ ,‘GAS’ ,6.579,‘MASS’,‘a’,
‘EVERYWHERE’, ‘ALL’ ,‘PNCOM’ ,‘PCVOC’ ,‘GAS’ ,6.579,‘MASS’,‘a’,
‘EVERYWHERE’, ‘ALL’ ,‘IVOB’ ,‘PCVOC’ ,‘GAS’ ,1,‘MASS’,‘a’,
‘EVERYWHERE’, ‘ALL’ ,‘IVOA’ ,‘PCVOC’ ,‘GAS’ ,1,‘MASS’,‘a’,
‘EVERYWHERE’, ‘ALL’ ,‘IVOG’ ,‘PCVOC’ ,‘GAS’ ,1,‘MASS’,‘a’,
‘EVERYWHERE’, ‘ALL’ ,‘IVOD’ ,‘PCVOC’ ,‘GAS’ ,1,‘MASS’,‘a’,

Hi Shu,

Sorry for the delayed response and thank you for reaching out. You are on the right track with your example above, but you may be double-counting emissions here. The IVOB, IVOA, IVOG, and IVOD are not species that are commonly output by SMOKE for use in the CMAQ system. Are they on your emission files already? If you would like for these variables to account for the IVOC emission, then I suggest commenting out the first two lines above that correspond to POC and PNCOM. You should also consider routing these emissions to the species called VIVPO1 which is an IVOC with C* = 10^3 ug m-3. This IVOC species will form SOA, but using a multigenerational oxidation style mechanism, not a single-generation SOA yield-type approach. If you are wanting to do something more standard using an IVOC yield from a particular literature reference, for example, let me know and I can try to help you add a species to CMAQ to handle this.

More importantly, it’s not clear to me why you would be seeing no difference using the configuration above. I recommend inspecting the log output (in any of the CTM_LOG_XXX files) to verify if these IVOC species were correctly identified on each input stream and scaled as expected. You can search for “INITIALIZE EMISSIONS MODULE” in the log file to find the relevant section. The subsections titled “Reading and Storing Emission Scaling Rules” and “EMISSIONS SCALING REPORT” are especially informative.