Hi Ben,
Really appreciate the reply!
(1) Got the idea of conversion between molar and mass yields. However, these values seem to be much lower than the corresponding SOA yields implemented in CAMx. For instance, on molar basis and under high NOx conditions, TOL yields 0.016 SVAVB2 (C*=1), 0.051 SVAVB3 (C*=10) and 0.047 SVAVB4 (C*=100). Whereas in CAMx, under the same condition, TOL yields 0.006 VAS1 (C*=1), 0.145 VAS2 (C*=10), 0.281 VAS3 (C*=100), and 0.432 VAS4 (C*=1000). These numbers seem to be different by an order of magnitude. Is there any reference for CMAQ’s SOA yields for TOL/XYL/BENZ? These values seem to be inconsistent (again lower) with Hodzic et al 2015 paper (Table 1) acp-16-7917-2016.pdf (copernicus.org)
-
You pointed out an important point that I didn’t realize earlier, that is in CMAQ, there is no such continuous aging from high volatility bins into low volatility bins (for example, from SVAVB4 → SVAVB3, from SVAVB3 → SVAVB2) for anthropogenic VOCs as implemented in CAMx. This might also cause smaller SOA formation in CMAQ, compared to CAMx?
-
As you mentioned the potential-combustion SOA species, I have been really confused with this. I looked into the CMAQ source code. It seems to me that “PCVOC” represents IVOC emissions and “PCSOA” represents the SOA formation from PCVOC emissions, correct? If I have separate estimate of IVOCs emissions, I should rename my IVOCs emissions as “PCVOC” in CMAQ so that CMAQ could incorporate SOA formation from IVOCs, correct?
Thanks
Ling