# CMAQ STM methods

**URL:** <https://forum.cmascenter.org/t/cmaq-stm-methods/2284>\
**Category:** Chemistry and Aerosols\
**Created:** [April 22, 2021, 3:53am UTC](https://forum.cmascenter.org/t/cmaq-stm-methods/2284 "2021-04-22T03:53:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![phy](https://avatars.discourse-cdn.com/v4/letter/p/35a633/32.png) [@phy](https://forum.cmascenter.org/u/phy)\
**Post date:** [April 22, 2021, 3:53am UTC](https://forum.cmascenter.org/t/cmaq-stm-methods/2284/1 "2021-04-22T03:53:01Z")

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Hi, all!

I have a question of running of CMAQ STM module.

I’m using the CMAQ v5.3.1 with STM option.  
And I found that if initial and boundary condition files include STM values not zero, they could affect the whole STM values in CONC file.

So, should I initialize all of STM species values by ‘0’ in initial boundary condition file ??

And I also want to know where the source of ‘ASO4ICBC’ in CMAQ-STM is.

I wish I can get any responses from you.

Thank you.

HyeonYeong Park