CMAQ STM species

Hi, all!
I have a question related to Sulfur Tracking Model(STM) species.
There are several species such as ‘ASO4AQH2O2J’, ‘ASO4AQGASI’, ‘ASO4AQFEMNJ’, ‘ASO4EMISJ’ etc.
Then, can I call these STM species ‘counter species’ in CMAQ ??

I’ve read CMAQ science documentation chapter 8 and 10.
And ‘counter species’ and ‘aerosol yields’ were introduced in these documentations.
So, I thought that STM species could be called ‘counter species’ or ‘aerosol yields’ in CMAQ.
But I’m so confused because I don’t know which one is correct.

Also, I want to know calculation method of these species concentration.
For example, in case of H2O2 aqueous-phase reaction of sulfate formation,
I think that ‘ASO4AQH2O2J’ concentration is calculated by a reaction such as
‘SO2 + H2O2 --> ASO4AQH2O2J+H2O’ in CMAQ chemical mechanism.
I want to know whether my thinking is right or not.

So, If you guys know about that, please let me know.


HyeonYeong Park

This table contains the reactions: (please click on the link)
Table 1. Sulfur Tracking Species

Hi, lizadams!
Thank you for your replying :slight_smile:
But I want to know whether STM species such as ‘ASO4AQH2O2J’ is calculated by independent reaction not ‘ASO4’ formation reaction.
So, I think that ‘ASO4AQH2O2J’ is calculated by the reaction ‘SO2+H2O2 --> ASO4AQH2O2J + H2O’. Is it right??? And this reaction is included in CMAQ source code???


Check inside the aqchem.F file for your CMAQ version. Inside, you will find the different pathways for SO2 oxidation in the aqueous phase. The rate for the H2O2 pathway is exactly:

    DSIVDT( 1 ) = -RH2O2 * H2O2L * HSO3 * HPLUS / ( 1.0D0 + 13.0D0 * HPLUS )

You can see it depends on various quantities that are also calculated in that subroutine.

I am not really sure I understand what exactly you are asking, so let me know if this is not helpful.


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Hi, sergey!
I’m so appreciate for your replying.
I’ve just checked aqchem.F of my CMAQ source file, and finally I found it!
Your replying is so helpful for me and that is a answer that I want. :slight_smile:
Once again, thank you for your replying :slight_smile:


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