# About Black carbon in CMAQ chemistry module

**URL:** <https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669>\
**Category:** CMAQ\
**Tags:** admin\
**Created:** [July 24, 2020, 10:54pm UTC](https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669 "2020-07-24T22:54:19Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\
**Post date:** [July 24, 2020, 10:54pm UTC](https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669/1 "2020-07-24T22:54:19Z")

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Hi all,  
Recently I am working on implementing black carbon emission into my CMAQ emission file. But I am a little bit confusing the effects of the addition of black carbon into the emission file. I mean, does it make sense to CMAQ model that providing the BC emission in the emission file and compare it without BC emission?  
I am also curious about how BC is treated in the current chemistry module in CMAQ. Does CMAQ5.3.1 account for its light absorption effects?  
Any suggestions are highly appreciated!

Best,  
Ryan

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**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\
**Post date:** [July 24, 2020, 10:54pm UTC](https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669/2 "2020-07-24T22:54:54Z")

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@hogrefe.christian @lizadams @Havala.Pye

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**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\
**Post date:** [July 28, 2020, 12:02am UTC](https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669/3 "2020-07-28T00:02:19Z")

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Can anyone help me with this issue or pass this issue to the expert who can handle it?  
Thanks!  
@cgnolte @hogrefe.christian

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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:** [July 28, 2020, 12:49pm UTC](https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669/4 "2020-07-28T12:49:06Z")

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Aerosol scattering and absorption of radiation are considered in are taken into account in CMAQ’s photolysis module. This is described in section 2.3 of [Appel et al. (2017)](http://doi.org/10.5194/gmd-10-1703-2017).

If using the two-way coupled WRF-CMAQ model, aerosols can also modify the thermal structure of the atmosphere, and hence the calculation of the boundary layer height and the extent of vertical mixing. There are several papers on this by Jia Xing that have been published in Atmos. Chem. Phys.

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**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\
**Post date:** [July 28, 2020, 10:28pm UTC](https://forum.cmascenter.org/t/about-black-carbon-in-cmaq-chemistry-module/1669/5 "2020-07-28T22:28:39Z")

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Hi Chris,  
Thanks for your response. I will check them out.  
I really appreciate your help!

Regards,  
Ryan