I am currently running the 2016v2 platform as input for CMAQ and am noticing some large differences in emissions and concentrations compared to a previous 2016_beta-CMAQ set up.
I first noticed model grid cells with airports having erroneously high NO emissions but then found (2017 Emissions Modeling Platform - CMASWIKI) which stated airport inventory from the 2017NEI was overestimating emissions at airports. Hopefully using the updated 2017gb emissions will resolve this issue.
However, I am also modeling high PM2.5 concentrations overall, especially near industrial point sources. I have not found documentation suggesting issues with the ptnonipm sector emissions but I am curious if anyone has any suggestions as to what is causing these elevated PM levels.
The 2016v2 platform has a lot of updates since the 2016 beta platform, and the 2016v3 platform has been released since 2016v2. Technical documentation for the platform and links to summaries are here: https://www.epa.gov/air-emissions-modeling/2016v2-platform
There are many emissions data summaries that should help you understand which sectors are causing high PM in certain areas here: Index of /Air/emismod/2016/v2/reports these include county-daily and county-monthly summaries. As you noted, the airport emissions are reduced in 2016v2 compared to 2016 beta. We aren’t sure why you would switch to 2017gb emissions - that shouldn’t be necessary as the reductions are already implemented in 2016v2.
Thank you for you response. After digging into the documentation a bit more I realize I created emissions using the aero 7 module as input into CMAQv5.2, which is using the previous aero 6 module. I believe this is likely the cause for excess PM2.5 in the simulation. Is there documentation available on how I can retrofit emissions using aero7 to work in CMAQv5.2? Thank you.
Using AERO7 emissions in AERO6 would likely cause 30% of your monoterpene emissions to be lost and I would expect you would underestimate PM2.5. So, there are definitely biogenic emission adjustments needed to switch between ae6/7, but it doesn’t sound like that is your major issue.
Here is the difference in the biogenic profiles: The corresponding speciation profile codes are B10C6 and BC6E7, respectively (shortened from B10C6AE7 related to the SMOKE profile code length issue we looked at recently). The main difference is that the AE7 profile outputs acetic acid and formic acid as their own species (AACD/FACD) instead of lumping with other species.
We think that the change in the emissions inputs between the two cases is the more likely cause of the change. Have you compared the total emissions by pollutant and sector to better understand the differences between the emissions inputs for the two cases?