How to simulate HAPs with cmaq

Hi All,

I want to simulate HAPs with cmaq, What modifications should I made to the cmaq compilation? and what HAP species should be available in the cmaq input emissions as primary emissions?


To utilize the full list of toxic air pollutants available in the CMAQ system you will need to use the cb6mp_ae6_aq chemical mechanism for simulations using CMAQ versions 5.3 through 5.3.3. See this table in the CMAQ GitHub repository for more information on cb6mp:

In CMAQv5.4, which will be released within the month, the chemical mechanism for simulations of HAPs will be updated to cb6r5hap_ae7_aq. Updates in this mechanism will be described in the v5.4 release notes.

Please see this page for a general overview of modeling HAPs in CMAQ.

To see what emissions are needed to simulate HAPS in CMAQ version 5.3.3, check the file, main/CCTM/src/MECHS/cb6mp_ae6_aq/EmissCtrl_cb6mp_ae6_aq.nml, where HAP species are listed. Note that CMAQ version 5.4 will use the file, main/CCTM/src/MECHS/cb6r5hap_ae7_aq/CMAQ_Control_DESID_cb6r5hap_ae7_aq.nml, to define this information.

Many thanks for the info. However, I am wondering why Benzop(a)pyrene is not in the namelist? Does it use different surrogate name. Because it is an important HAP , but I can not find it in the Emissctrl file. Thanks

Thanks Kristen this is quite helpful. BTW is there any GSPRO and GSREF created for this mechanism? I have emissions but I am not quite sure about speciation. For instance I have total Nickel emissions but I don’t how much should go to Fine mode or coarse mode in smoke.

In the to be released CMAQ version 5.4, Benzo(a)pyrene is represented in the NR and AE species namelists for the cb6r5hap_ae7_aq mechanism. The species are BENAPY and ABENAPY. The latter aerosol species has Aitken and Accumulation modes. In the emissions control file, CMAQ_Control_DESID_cb6r5hap_ae7_aq.nml, benzo[a]pyrene emissions go into the gas phase species, BENAPY via the below line.

 'EVERYWHERE', 'ALL' ,'BENZOAPYRNE','BENAPY',             'GAS'  ,1.  ,'UNIT','a',

Within CMAQ, benzo[a]pyrene will partition between the gas phase species and the two aerosol phase species.

If you want the aerosol species to have emissions, you have to add their instructions to emissions control file. In version 5.4, Chapter 4 and section 8 gives information and links on editing the control file.

Great and Many Thanks for the information. :slightly_smiling_face:

Just my final question. Is there any GSPRO and GSREF example files for cb6mp_ae6_aq or cb6r5hap_ae7_aq?

Hi @nosha_assare , I think we should be able to provide those GSPRO and GSREF example files. I am trying to track them down and will hopefully have something to share next week.

Many thanks Kritsten. That would be quite helpful.

Kind Regards,

Hi Nosha,
This zip contains GSPROs and GSREFs for CMAQ multipollutant (a.k.a. HAP-CAP) that will hopefully meet your needs.

This is from the 2017 emissions modeling platform: 2017 Emissions Modeling Platform | US EPA

Hi Kristen,

Many thanks for your help.


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@foley.kristen @bhutzell since H-cmaq files does not include HAP species, I am wondering should I adjust initial and boundary data to include those species? or is there any specific data to be used as ic/bc for HAP modelling? Thanks

Hi Nosha,
The multipollutant version of CMAQv5.3.1 was used for EPA’s 2017 Air Toxics Screening Assessment (AirToxScreen). This Technical Support Document describes how the IC/BCs were handled for that application (section 3.3.2, page 62):

If you have further questions on the set up for that application, I believe you should be able to use the ‘contact us’ link on this page: AirToxScreen Technical Support Document | US EPA
Or you can also continue to post on this thread.
Good luck with your project!

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