# Some question about CCTM in CMAQv5.2 **URL:** \ **Category:** MEGAN\ **Tags:** cmaq\ **Created:** [December 9, 2024, 8:27am UTC](https://forum.cmascenter.org/t/some-question-about-cctm-in-cmaqv5-2/5423 "2024-12-09T08:27:10Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Sunchanglei](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.cmascenter.org/sunchanglei/32/4358_2.png) [@Sunchanglei](https://forum.cmascenter.org/u/Sunchanglei)\ **Post date:** [December 9, 2024, 8:27am UTC](https://forum.cmascenter.org/t/some-question-about-cctm-in-cmaqv5-2/5423/1 "2024-12-09T08:27:10Z")
Hello everyone, I have recently started to learn CCTM, and I have some simple questions to ask you 1. I have finished running the last step of MEGAN3.2, run.mgn2mech.v32.csh, and finally generated the ncf file. Could this ncf file be directly used as the input file of CMAQ? 2. How to turn off the biogenic VOC generated by default BEIS in CMAQ? Because I wanted to use my own MEGAN’s. 3. Is the output file In MEGAN where it is placed in the in-line biogenic emissions configuration in the cctm script? The question may be very simple for all teachers, but it is of great help to me. I look forward to your answers! I am using version 5.2 of CMAQ ---
**Author:** ![willison.jeff](https://avatars.discourse-cdn.com/v4/letter/w/c89c15/32.png) [@willison.jeff](https://forum.cmascenter.org/u/willison.jeff)\ **Post date:** [December 9, 2024, 1:28pm UTC](https://forum.cmascenter.org/t/some-question-about-cctm-in-cmaqv5-2/5423/3 "2024-12-09T13:28:44Z")
1. Yes, the emissions from mgn2mech are supposed to be usable with CMAQ. 2. In CMAQ 5.2 the option to turn off BEIS was 3. The MEGAN output can be read similar to other emissions, or merged with another emissions file. [See this thread](https://forum.cmascenter.org/t/use-megan-generated-biogenic-emissions-in-cmaq/969) for further discussion. Newer versions of CMAQ allow for MEGAN version 3.2 to be run online, which is much simpler.