# Evaluation

**URL:** https://forum.cmascenter.org/c/cmaq/evaluation/57.md

[Latest](https://forum.cmascenter.org/latest.md) · [Categories](https://forum.cmascenter.org/categories.md) · [Tags](https://forum.cmascenter.org/tags.md)

---

## [About the Evaluation category](https://forum.cmascenter.org/t/about-the-evaluation-category/2067)

<div class="topic-metadata">

**Author:** [@foley.kristen](https://forum.cmascenter.org/u/foley.kristen)\
**Replies:** 0

</div>

---

## [PM2.5 calculation in CMAQ version 5.3.1](https://forum.cmascenter.org/t/pm2-5-calculation-in-cmaq-version-5-3-1/5904)

<div class="topic-metadata">

**Author:** [@active3734](https://forum.cmascenter.org/u/active3734)\
**Replies:** 3\
**Last updated:** [July 15, 2025, 5:27am UTC](https://forum.cmascenter.org/t/pm2-5-calculation-in-cmaq-version-5-3-1/5904 "2025-07-15T05:27:57Z")

</div>

My colleague used CMAQ version 5.3.1 and shared the output data with me. I want to calculate PM2.5 using the variables in this output file and proceed with my research. As I understand, PM2.5 is basically calculated as…

---

## [How to Compute PM2.5 Source Contributions Using IPR in CMAQ?](https://forum.cmascenter.org/t/how-to-compute-pm2-5-source-contributions-using-ipr-in-cmaq/5906)

<div class="topic-metadata">

**Author:** [@active3734](https://forum.cmascenter.org/u/active3734)\
**Replies:** 1\
**Last updated:** [July 11, 2025, 5:12pm UTC](https://forum.cmascenter.org/t/how-to-compute-pm2-5-source-contributions-using-ipr-in-cmaq/5906 "2025-07-11T17:12:14Z")

</div>

I found the PM2.5 calculation method in the file SpecDef\_cb6r3\_ae7\_aq.txt, and the formula is as follows: PM25\_TOT = ATOTI\[0\] \* PM25AT\[3\] + ATOTJ\[0\] \* PM25AC\[3\] + ATOTK\[0\] \* PM25CO\[3\] However, I couldn’t find any formu…

---

## [Large Discrepancy between CMAQ and ARM O₃ Measurements](https://forum.cmascenter.org/t/large-discrepancy-between-cmaq-and-arm-o-measurements/5798)

<div class="topic-metadata">

**Author:** [@azurebullet](https://forum.cmascenter.org/u/azurebullet)\
**Replies:** 14\
**Last updated:** [May 13, 2025, 6:51pm UTC](https://forum.cmascenter.org/t/large-discrepancy-between-cmaq-and-arm-o-measurements/5798 "2025-05-13T18:51:34Z")

</div>

Hi everyone, I am comparing CMAQ model outputs with ARM SGP measurements for O₃ (Ozone) concentrations from April 22 to May 22, 2016. My analysis shows CMAQ values are consistently much higher than ARM, often in the 10⁴…

---

## [Turning off process like Dry Deposition or BC in CMAQ](https://forum.cmascenter.org/t/turning-off-process-like-dry-deposition-or-bc-in-cmaq/2599)

<div class="topic-metadata">

**Author:** [@skunwar](https://forum.cmascenter.org/u/skunwar)\
**Replies:** 1\
**Last updated:** [August 23, 2021, 3:28pm UTC](https://forum.cmascenter.org/t/turning-off-process-like-dry-deposition-or-bc-in-cmaq/2599 "2021-08-23T15:28:48Z")

</div>

What would be the right way to switch off a process like dry deposition altogether, or just switch off ozone dry deposition to leaves stomata only in CMAQ (newest version)? What is the easiest way of setting input CMAQ …