How to compare sensitivity of O3 to VOC between CMAQ/DDM and CAMx/DDM

I am utilizing CMAQ/DDM version to conduct sensitivity of O3 to NOx and VOC. My intention is to compare the model results with those from CAMx/DDM version 7.0. However, I’m encountering challenges when attempting to compare the sensitivity of O3 to total VOC. This complexity arises due to disparities in the VOC species listed within the sensitivity control files, as well as differences in the chemistry mechanisms employed by the two models. The VOC species outlined in the respective models are provided below. Given this scenario, I’m contemplating the feasibility of directly comparing sensitivity outcomes between these two models. Please let me know if you have any ideas on this topic. Thanks.

26 VOC species in cb6r5_ae7_aq used in CMAQ v5.4
'ALD2 ','ALDX ','ETH ', 'ETHA ','ETOH ','FORM ','IOLE ','ISOP ', 'MEOH ','OLE ','PAR ','TERP ','TOL ', 'XYLMN ','NAPH ','ETHY ','PRPA ','ACET ', 'KET ','GLY ',‘BENZENE’,'GLYD ','MEPX ', 'APIN ','SOAALK ','MGLY '/

19 VOC species in CB6r4 used in CAMx v7.0
‘PAR’, ‘ETHA’, ‘MEOH’, ‘ETOH’, ‘ETH’, ‘OLE’, ‘IOLE’, ‘ISOP’, ‘TERP’, ‘FORM’, ‘ALD2’, ‘ALDX’, ‘TOL’, ‘XYL’, ‘PRPA’, ‘BENZ’, ‘ETHY’, ‘ACET’, ‘KET’

There have been other published efforts that compared CMAQ and CAMx that tried to reconcile mechanism and species lumping differences. It might be helpful to scan through the literature for that. The DDM sensitivity code does not specifically label any species as VOCs, because there is no need to do so.



I appreciate your prompt response. I am currently in the process of reviewing papers that compare CMAQ and CAMx. I will read more to gain a more comprehensive understanding.

You’re correct, the DDM sensitivity code doesn’t explicitly categorize any species as VOCs. In our efforts to explore methods for the possibility of reducing VOC emissions and implementing VOC emission control strategies, my focus usually extends beyond individual VOC species. Our aim is to curtail overall emissions, encompassing all VOCs or the total VOC.

This rationale underscores my intention to delve into the DDM sensitivity of VOCs as a collective entity, which encapsulates all VOC species, in relation to ozone. Does this approach make sense?


That sounds like a fine approach to me.