Use case of CO2_INV

Hi there,

I was wondering if CO2_INV would be the appropriate marker for change in CO2 from two sensitivity runs from the CMAQ output?

I was not sure because for example, you need the haps mechanism to convert the various chemically-active species (like HCHO) into HCHO_HAP for health processing. Is there a similar mechanism I would have to use to convert CO2_INV into something else I would use to describe changes in CO2 due to a sensitivity? Or is it fine just calculating changes as-is?

Thank you!

I’m not really understanding your question with this. CO2 would depend on the sectors of interest. CO2 is not included in the inventory for most nonpoint sources, while CO is…

Hi Alison,

Thanks for letting me know this. I have several versions of the SMOKE platforms, and when I calculate emissions, included in the output of the combined (emis_mol_all*) and point source files (pt_*) is a variable called CO2_INV.

And to calculate changes of CO2, I have been looking at specific sectors that have inputs and outputs of CO2. Specifically, I have been looking at vehicle emissions, so in the documentation there exists ‘atmospheric CO2’ and ‘co2 equivalents’ within the onroad sector and moves processes: 2.8.4. Mobile-source processing using MOVES
SMOKE-MOVES/pollutant_mapping_NEI.csv at master · CEMPD/SMOKE-MOVES · GitHub

So given what you’ve touched on, my clarification question is: if I run a sensitivity simulation that targets emissions from vehicles, I could calculate the change in CO2 by comparing the variable CO2_INV in the output because it’s estimated in the moves process. I could not say what is the total amount of CO2 emissions coming from everything (cuz it’s not reported), but I could talk about relative differences from this specific intervention. Right?

And then to your second point: in contrast, I wouldn’t be able to calculate CO2 changes from area sources that do not report CO2 and I cannot calculate total CO2 emissions from all activity (so the output only has only a portion of the total estimate of CO2 emissions). And, I would only be able to tell if the CO2 emissions are in an inventory by inspecting the intermediate output or by close reading the NEI documentation of what is reported by sector.

If CO2 is included for the sources of interest, then yes you could examine the differences in the outputs of the two runs, or for a specific sector that includes CO2 emissions. For onroad, you would likely keep all of the other inputs the same (aside from the one you are varying) to determine the impact of a particular intervention. I just mention this because you said you had several platforms involved.

For most sectors (although not onroad), you can review the input inventory for CO2. Onroad is different because the emissions are not input, instead activity data and emission factors are input.

Hopefully that helps…