Treating PM2.5 as a "single species" for fine-mode PPM simulation in CMAQ 5.4

Hello everyone!

I am trying to simulate fine mode primary particulate matter (PPM, i.e., without considering the chemical reaction and secondary aerosol formation process and only considering transport, advection, diffusion, and deposition) over Eastern Asia with CMAQ 5.4. As there is not a straightforward method, I am trying some possible ways and inter-comparing their results. Now I am adding an aerosol tracer in the AE namelist, following the instruction from this CMAS forum page Adding Aerosol Tracer. The basic idea is to add a new aerosol species named “NTRA” in the following three files (AE_cb6r5_ae7_aq.nml, CMAQ_Control_DESID_cb6r5_ae7_aq.nml, AERO_DATA.F) assuming that the variable PM2.5 (not including OC and EC) in the gridded-inventory (Named “PMFine2” in my CMAQ-ready inventory) will not react with other gases and aerosols.
Major modifications to files are as follows.

In AE_cb6r5_ae7_aq.nml:

 'NTRA'    ,100.00  ,T     ,T     ,F      ,''     ,''     ,-1    ,''     ,-1     ,'VMASS'     , 1  ,'PRI'         , 1  ,''         ,'Yes'   ,'Yes'   ,'Yes'   ,'Yes'

In CMAQ_Control_DESID_cb6r5_ae7_aq.nml

 ! Region      | Stream Label  |Emission | CMAQ-        |Phase/|Scale |Basis |Op  
 !  Label      |               |Species  | Species      |Mode  |Factor|      |     
   'EVERYWHERE', 'ALL'         ,'PMFINE2','NTRA'        ,'FINE',1   ,' UNIT','a',

In AERO_DATA.F (line 362):

C                                                                                           Visidx_Large
C                                                                               no_M2Wet Tracer        |
C                                                                                       | | Charge      | OM           
C                      Name      T A C Min_Con Density Gas-Name   CTR-Name  Yield Vol   | |   | Visidx  |  |  OptSurr   korg  
C                     ---------- - - - ------- ------- ---------- --------- ----- ----- + +   + ------ --- +  -------- ----- 
     & spcs_list_type('NTRA    ',T,T,F, cm_set, 2200.0, '       ','       ',0.0  ,'NVL',F,T,  0,  0.0, 0.0,F, 'DUST  ', 0.00), ! Newly added tracer

My question is,

  1. Are my steps taken above reasonable enough to realize my goal (3-hourly Primary PM2.5 mass concentration simulation)
  2. If so, how to specify the value of fields “MOLWT” and “AE2AQ SURR” in the AE_cb6r5_ae7_aq.nml if I assume PM2.5 in the inventory as a “species”?

The following files are my log file and preliminary results (NTRA for aitken and accumulation modes respectively).
CTM_LOG_007.v54_intel_2019EastAsia_5_20190529.txt (491.3 KB)

Any comments will be appreciated.