# Questions about the MEGAN input file **URL:** \ **Category:** MEGAN\ **Created:** [December 5, 2024, 2:29am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413 "2024-12-05T02:29:12Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![whr](https://avatars.discourse-cdn.com/v4/letter/w/22d042/32.png) [@whr](https://forum.cmascenter.org/u/whr)\ **Post date:** [December 5, 2024, 2:29am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/1 "2024-12-05T02:29:12Z")
Dear all, I have recently been using MEGAN 3.2 with CMAQ. My simulation domain is located in Asia. I noticed that there are two different input datasets for MEGAN 3.2 : [MEGAN 3.2 input files](https://zenodo.org/records/10939297) and [MEGAN Input Data Version 2310](https://zenodo.org/records/10375519). After testing, I found that using these two sets of input datasets will give very different results. Which input datasets should I use when simulating Asia with MEGAN 3.2 in CMAQ? I would appreciate your advice. Haorui Wang 2024.12.05 ---
**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 5, 2024, 2:49am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/2 "2024-12-05T02:49:25Z")
Thank you for sharing these datasets. I’m not sure what differentiates them from each other or from earlier versions that were distributed from their website. That would be a good question for Alex Guenther. I assume the newer ones ([MEGAN 3.2 input files](https://zenodo.org/records/10939297)) would be the preferred versions. ---
**Author:** ![whr](https://avatars.discourse-cdn.com/v4/letter/w/22d042/32.png) [@whr](https://forum.cmascenter.org/u/whr)\ **Post date:** [December 5, 2024, 2:55am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/3 "2024-12-05T02:55:58Z")
Dear [willison.jeff](https://forum.cmascenter.org/u/willison.jeff), Thanks so much for your reply! I have contacted Alex Guenther via email. I will share any response here once I get it. ---
**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 5, 2024, 3:01am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/4 "2024-12-05T03:01:21Z")
Great! I’m excited to try these new ones. Thanks again for sharing. ---
**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 5, 2024, 3:12pm UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/5 "2024-12-05T15:12:47Z")
The newest inputs seem to generate even higher monoterpene emission factors over CONUS 😞 ---
**Author:** ![whr](https://avatars.discourse-cdn.com/v4/letter/w/22d042/32.png) [@whr](https://forum.cmascenter.org/u/whr)\ **Post date:** [December 6, 2024, 5:20am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/6 "2024-12-06T05:20:12Z")
Yes, the new simulation results for the Asian domain are also very different from before, with emissions in some areas increasing significantly. It currently looks like there are 3 sets of input data. I’m not sure whether to use the original version distributed on the official website or the 2 sets of input data I mentioned at the beginning of this post. Professor Alex Guenther has not replied to me yet. I have less experience with Megan. Do you have any advice based on your experience? ---
**Author:** ![Ryan](https://avatars.discourse-cdn.com/v4/letter/r/a8b319/32.png) [@Ryan](https://forum.cmascenter.org/u/Ryan)\ **Post date:** [December 12, 2024, 8:22am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/7 "2024-12-12T08:22:08Z")
Professor Alex Guenther is on sabbatical. Therefore, it may take a while for you to get a response from him. ---
**Author:** ![whr](https://avatars.discourse-cdn.com/v4/letter/w/22d042/32.png) [@whr](https://forum.cmascenter.org/u/whr)\ **Post date:** [December 12, 2024, 8:53am UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/8 "2024-12-12T08:53:24Z")
Dear [Ryan](https://forum.cmascenter.org/u/Ryan) Thank you so much. ---
**Author:** ![whr](https://avatars.discourse-cdn.com/v4/letter/w/22d042/32.png) [@whr](https://forum.cmascenter.org/u/whr)\ **Post date:** [December 12, 2024, 12:49pm UTC](https://forum.cmascenter.org/t/questions-about-the-megan-input-file/5413/9 "2024-12-12T12:49:51Z")
Professor Alex Guenther replied to me. He said “These data sets were developed for specific case studies in the U.S. I have not created any input data for Asia. I am working on publishing a paper describing MEGAN3.2 and am not able to provide any support for the model until after it is published.” Therefore, I think using the original version of the input data obtained from the official website is more appropriate for Asia or global modeling.