# Low simulated PM2.5 concentrations of CMAQ results **URL:** \ **Category:** CMAQ\ **Tags:** cmaq\ **Created:** [May 26, 2024, 3:10pm UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965 "2024-05-26T15:10:07Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Jason\_Hu](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@Jason\_Hu](https://forum.cmascenter.org/u/Jason_Hu)\ **Post date:** [May 26, 2024, 3:10pm UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/1 "2024-05-26T15:10:07Z")
Hello everyone, I get a question about CMAQ results. I have tried to simulate PM2.5 for several times using CMAQ, but all got low concentrations. However, the simulated PM2.5 from WRF-Chem are comparable with observations during the same period. I wonder if there are some errors of my emission files or errors from my run\_cctm.csh setting. Actually, I have double checked my emission files, and the value is comparable with the value in some references. [run\_cctm\_hj.csh.txt](https://forum.cmascenter.org/uploads/short-url/sp4Lp4j4E87jiTYoUQ3Q57GjHWQ.txt) (35.6 KB) ---
**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 28, 2024, 1:05pm UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/2 "2024-05-28T13:05:44Z")
Take a look at one of the processor-specific log files, e.g., CTM\_LOG\_000. Look for the section where emissions are being read, and check to see if the model reports that key species are not found. What mechanism did you use in compiling the model, and does that match your emissions species? If this does not help, provide more details, including model version and log files. Please also see the “PLEASE READ before posting” [message](https://forum.cmascenter.org/t/please-read-before-posting/1321). ---
**Author:** ![Jason\_Hu](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@Jason\_Hu](https://forum.cmascenter.org/u/Jason_Hu)\ **Post date:** [May 29, 2024, 1:11am UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/3 "2024-05-29T01:11:46Z")
I used cb6r3\_ae7\_aq in compiling the CMAQ-5.3.2, and also CB6\_AE7 emissions species are used in the model. According the log file attached below, I think emissions are all being read in CMAQ. [CTM\_LOG\_249.v532\_gcc\_2022XZQ\_20220112.txt](https://forum.cmascenter.org/uploads/short-url/xUx4ouDY9UCR0rH509cxOLVpTJp.txt) (1.6 MB) ---
**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 29, 2024, 6:24pm UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/4 "2024-05-29T18:24:07Z")
We do not see anything obvious in your log file. Here are a few ideas that may help in debugging. - You might try turning on emissions diagnostic files and verify that the totals are as you expect. - How low are the PM2.5 concentrations, and what values are you obtaining using WRF-Chem? Are all PM components low, or is the problem mostly inorganics, organics, or unspeciated PM? - What physics options are you using with WRF-Chem? It is possible you are using a configuration that is not handled well by MCIP and CMAQ. ---
**Author:** ![Jason\_Hu](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@Jason\_Hu](https://forum.cmascenter.org/u/Jason_Hu)\ **Post date:** [July 30, 2024, 1:47am UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/5 "2024-07-30T01:47:28Z")
Thanks a lot. I have set these. `setenv EMISDIAG T` `setenv EMISDIAG_SUM T` I found there is only one layer in CCTM\_EMDIAG files, but it’s 10 layers in my emission files. Are there some errors with my setting ? ---
**Author:** ![Jason\_Hu](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@Jason\_Hu](https://forum.cmascenter.org/u/Jason_Hu)\ **Post date:** [July 30, 2024, 1:56am UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/6 "2024-07-30T01:56:21Z")
[run\_cctm\_hj.csh](https://forum.cmascenter.org/uploads/short-url/c1jAzZndTMUSuDgCPqTux0f65K1.csh) (37.1 KB) This is my new running script. ---
**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 30, 2024, 2:22am UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/7 "2024-07-30T02:22:29Z")
The interface has changed since then, but I believe in the version of CMAQ you are using, if you want the EMISDIAG files to be 3D rather than column sums, then use `setenv EMISDIAG 3D` ---
**Author:** ![TJDOFLEARN](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@TJDOFLEARN](https://forum.cmascenter.org/u/TJDOFLEARN)\ **Post date:** [March 8, 2025, 2:00am UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/8 "2025-03-08T02:00:40Z")
Hey sir I met a problem about low concentrations of pm25. I want ask you help. my run\_script is [run\_cctm.csh](https://forum.cmascenter.org/uploads/short-url/dBRAVHWfGwSIgsI72PeGtxsqv5F.csh) (39.4 KB) my run\_log is [CTM\_LOG\_000.txt](https://forum.cmascenter.org/uploads/short-url/fhrCQZR8sfH7AvvvyYm2Ef3I4Xu.txt) (2.0 MB) thanks for you reading ---
**Author:** ![hogrefe.christian](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@hogrefe.christian](https://forum.cmascenter.org/u/hogrefe.christian)\ **Post date:** [March 9, 2025, 4:25pm UTC](https://forum.cmascenter.org/t/low-simulated-pm2-5-concentrations-of-cmaq-results/4965/10 "2025-03-09T16:25:39Z")
> [@TJDOFLEARN](#): > > Hey sir > I met a problem about low concentrations of pm25. I want ask you help. > my run\_script is > [run\_cctm.csh](https://forum.cmascenter.org/uploads/short-url/dBRAVHWfGwSIgsI72PeGtxsqv5F.csh) (39.4 KB) > my run\_log is > [CTM\_LOG\_000.txt](https://forum.cmascenter.org/uploads/short-url/fhrCQZR8sfH7AvvvyYm2Ef3I4Xu.txt) (2.0 MB) > thanks for you reading Please do not create duplicate posts. You already asked this question in a [new thread you created](https://forum.cmascenter.org/t/cmaq-simmulation-concentation-of-pm25-too-low/5654). Adding the same question to an existing older thread only leads to clutter and will not provide you with a faster response.