Hi,
My question is a bit similar than the one posted in https://forum.cmascenter.org/t/questions-on-windblown-dust-and-pm10-calculation-by-cmaq/1750; but I do not find the useful information in the replies.
Is it possible to calculate the dust contribution in PM2.5 as we can calculate the SIA or other components with the combine postprocessing script?
For example, Foroutan et al. (2017) (doi:10.1002/2016MS000823) does not show « dust » concentrations and to illustrate a dust plume, this website (Windblown Dust in CMAQ | CMAQ: The Community Multiscale Air Quality Modeling System | US EPA) only presents the ASOILJ concentrations.
Does it mean PM25_SOIL corresponds to the PM25 dust ?
I use CMAQv5.3.1.
Best regards,
Matthieu
Hello Matthieu,
I think you are asking whether there is a way to isolate and quantify the contribution of windblown dust emissions to the PM concentrations in the standard CMAQ output files. If that is the question, the answer is that generally this is not possible.
The reason for this is that the crustal species emitted in the windblown dust module (see table dust_spc on lines 426 - 456 of AERO_DATA.F) are also emitted from certain anthropogenic primary PM sources. Put differently, none of the CMAQ PM concentration species is a unique tracer for windblown dust emissions.
That said, depending on the relative abundance of windblown dust emissions and anthropogenic primary PM emissions in a given area and time period, the “ASOILJ” combination defined in combine as combination of AALJ, ASIJ, ACAJ, AFEJ, and ATIJ and/or the CMAQ species AOTHRJ can be used as a proxy for concentration variations caused by windblown dust emissions if windblown dust emissions of these species in the area and time period of interest dominate over anthropogenic sources. The ASOILJ quantify has the added advantage that it can be compared to an equivalent observed quantify derived from the same trace elements measured at PM speciation monitors. This was the approach taken in the Foroutan et al. (2017) study that focused on areas and time periods heavily influenced by windblown dust emissions.
To directly quantify the contribution of windblown dust emissions to ambient PM concentrations, you would want to employ ISAM configured to track windblown dust emissions and/or perform a brute force sensitivity simulation in which you zero out primary PM emissions from all sources except windblown dust.
I apologize if I misunderstood your question.
2 Likes
Thank you very much.
Yes, you have understood my question. This is helpful!
Hy @hogrefe.christian ,
I have similar type question. I am using CMAQ v5.4 HDDM module to estimate PM2.5 from EGU emissions. Please see the attached sensitivity file.
sensinput.ptegu.dat.txt (2.4 KB)
I would like to quantify PM2.5 from EGU emissions using higher order sensitivity (from NOx emissions, from SO2 emissions and then for in combination of NOx and SO2 emissions). I am not sure how to set input file in COMBINE post processing tools. I get following output files from CCTM run.
When I use COMBINE post processing tool to calculate PM2.5 from all sources, it takes ACONC, METCRO3D, AELMO and METCRO2D file. The formula from SpecDef_cb6r3_ae7_aq.txt file showing, for example, PM25_SO4 ,ug m-3 ,PM25_SO4[3]. Here, [3] is AELMO file that I got from CCTM output. From my, ASENS file I get following output variables.
My question is, how do I use COMBINE post processing tools to quantify PM2.5 using HDDM sensitivity files?
Regards,
Rasel
To calculate PM2.5 from individual PM components stored in CMAQv5.4 DDM or ISAM files, you need to go back to the equations in the CMAQv5.3.3 SpecDef files (e.g. this one).
If you are interested in calculating sharp cut-off PM2.5 species, you need to use the FPM25AIT, FPM25ACC, and FPM25COR variables from the CMAQv5.4 AELMO files instead of the PM25AT, PM25AC, and PM25CO variables referenced in that SpecDef file and stored in the CMAQv5.3.3 APMDIAG files.
Please see the following threads for additional information on how to calculate PM2.5 for DDM or ISAM in CMAQv5.4 (note that while these posts discuss ISAM, the same approach holds true for calculating PM2.5 from the DDM output stored in the ASENS files):
Questions about PM2.5 calculation in CMAQv5.4 cb6r5AERO7 mechanism
How to get total pm10/pm25 from cmaq v5.4_isam output
How to get PM2.5_TOT from CMAQ5.4-ISAM outputs by combine?
Thank you @hogrefe.christian
Regards,
Rasel
