# Abnormal Simulation Result
**URL:** https://forum.cmascenter.org/t/abnormal-simulation-result/4314
**Category:** CMAQ
**Tags:** emissions, cmaq
**Created:** [August 20, 2023, 3:05am UTC](https://forum.cmascenter.org/t/abnormal-simulation-result/4314 "2023-08-20T03:05:21Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@lifenx](https://forum.cmascenter.org/u/lifenx)
#### Post date: [August 20, 2023, 3:05am UTC](https://forum.cmascenter.org/t/abnormal-simulation-result/4314/1 "2023-08-20T03:05:21Z")
Hi everyone,
I am trying to simulate PFAS pollution in China using the CMAQ-PFAS version. The model works, but the simulation results for PFAS species are very low, like a background value. The simulation results of each species are in the order of 1e-30~1e-19ppmv, I don‘t know what the problem is, anyone with experience can help me？
This question has bothered me for a long time, thank you in advance.
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### Author:  [@lizadams](https://forum.cmascenter.org/u/lizadams)
#### Post date: [November 10, 2023, 9:30pm UTC](https://forum.cmascenter.org/t/abnormal-simulation-result/4314/2 "2023-11-10T21:30:46Z")
Please share your run script settings, and also your build script. Please also review the following issue that mentions a requirement to use stage as the deposition module. [Tracer namelist in CMAQ5.2 - #13 by lifenx](https://forum.cmascenter.org/t/tracer-namelist-in-cmaq5-2/1377/13)