# Adding new gas species to CMAQ

**URL:** <https://forum.cmascenter.org/t/adding-new-gas-species-to-cmaq/5819>\
**Category:** CMAQ\
**Created:** [May 21, 2025, 8:23pm UTC](https://forum.cmascenter.org/t/adding-new-gas-species-to-cmaq/5819 "2025-05-21T20:23:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ganghan2000](https://avatars.discourse-cdn.com/v4/letter/g/e9bcb4/32.png) [@ganghan2000](https://forum.cmascenter.org/u/ganghan2000)\
**Post date:** [May 21, 2025, 8:23pm UTC](https://forum.cmascenter.org/t/adding-new-gas-species-to-cmaq/5819/1 "2025-05-21T20:23:42Z")

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Hello,

I’m trying to add a few semi-volatile gas species to improve the prediction of SOA formation.  
In the process, I found the Henry’s constant and enthalpy part in m3dry.F related to the dry deposition and wet deposition.

I know that CMAQ tables are scattered to different sections, and is there any sections to search and modify to add species correctly?

Thank you.

Ganghan

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**Author:** ![cgnolte](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.cmascenter.org/cgnolte/32/53_2.png) [@cgnolte](https://forum.cmascenter.org/u/cgnolte)\
**Post date:** [May 22, 2025, 1:47pm UTC](https://forum.cmascenter.org/t/adding-new-gas-species-to-cmaq/5819/2 "2025-05-22T13:47:17Z")

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Please see this [tutorial](https://github.com/USEPA/CMAQ/blob/main/DOCS/Users_Guide/Tutorials/CMAQ_UG_tutorial_chemicalmechanism.md).

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**Author:** ![system](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/1X/9a72c78e529465c3f1053af404e3033b0875428c.png) [@system](https://forum.cmascenter.org/u/system)\
**Post date:** [May 29, 2025, 1:47pm UTC](https://forum.cmascenter.org/t/adding-new-gas-species-to-cmaq/5819/3 "2025-05-29T13:47:48Z")

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