[QUESTION] Are SO4D1-D4 included in PM2.5?

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GEOS-Chem "Science Codebase" repository. Contains GEOS-Chem science routines, run directory generation scripts, and interface code. This repository is used as a submodule within the GCClassic and GCHP wrappers, as well as in other modeling contexts (external ESMs).

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[QUESTION] Are SO4D1-D4 included in PM2.5? #1058

Closed lixiao-bit closed 2 years ago

lixiao-bit commented 2 years ago

Ask a question about GEOS-Chem:

Hello!

Are SO4D1-SO4D4 included in the calculation of PM25 in GC, or only SO4?

This is the default calculation in the model:

"PM25 = ( NH4 + NIT + SO4 ) * 1.10

BCPI
BCPO
( OCPO + ( OCPI 1.05 ) ) (OM/OC ratio) # OM/OC ratio = 2.1 by default
DST1
DST2 * 0.30 # F. Yu suggests 30% of DST2 (Nov 2011); prior value was 38% of DST2
SALA * 1.86
SOA * 1.05"

I think there are some problems with this way of calculating

I am not sure the factor for SO4D1-SO4D4 should follow SO4's factor or the DST1-DST4's factor, as shown below:

"PM25 = ( NH4 + NIT + SO4+ SO4D1 + SO4D2 + SO4D3 + SO4D4 ) * 1.10

BCPI
BCPO
( OCPO + ( OCPI 1.05 ) ) (OM/OC ratio) # OM/OC ratio = 2.1 by default
DST1
DST2 * 0.30 # F. Yu suggests 30% of DST2 (Nov 2011); prior value was 38% of DST2
SALA * 1.86
SOA * 1.05"

"PM25 = ( NH4 + NIT + SO4 ) * 1.10

BCPI
BCPO
( OCPO + ( OCPI 1.05 ) ) (OM/OC ratio) # OM/OC ratio = 2.1 by default
DST1 + SO4D1
(DST2 + SO4D2) * 0.30 # F. Yu suggests 30% of DST2 (Nov 2011); prior value was 38% of DST2
SALA * 1.86
SOA * 1.05"

thank you.

yantosca commented 2 years ago

Thanks for writing @lixiao-bit. I would run this by the Aerosols Working Group (@theloniuspunk @beckyalexander).

Also note: the SO4D1-D4 species are only used for the simulation with dust aciduptake, which is maintained by the community, and is not covered by our regular benchmarking process. So it is possible that the PM2.5 may need to be updated for the aciduptake simulations.

theloniuspunk commented 2 years ago

Becky may have a better feel for this, but I think that the first option (( NH4 + NIT + SO4+ SO4D1 + SO4D2 + SO4D3 + SO4D4 ) * 1.10) makes more sense.

beckyalexander commented 2 years ago

Yes, the first option makes sense. I'm not sure though what the size bins are for SO4D1, etc. Only the size bins less than 2.5 microns should be included.

theloniuspunk commented 2 years ago

Right! Good call Becky! They should use the bin fractions used for dust.

On Fri, Dec 10, 2021 at 4:10 PM beckyalexander @.***> wrote:

Yes, the first option makes sense. I'm not sure though what the size bins are for SO4D1, etc. Only the size bins less than 2.5 microns should be included.

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lixiao-bit commented 2 years ago

thanks for hearing from you.

the radius of SO4D1 SO4D2 SO4D3 SO4D4 is defined as 0.7, 1.4, 2.4 and 4.5 microns in species_data.yml. considering this information, I consider that SO4D1 should be treated the same as DST1, SO4D2 should be treated the same as DST2, SO4D3 should be treated the same as DST3, SO4D4 should be treated the same as DST4 when calculate PM2.5. That is to say, in my opinion, PM2.5 should be calculated as below:

"PM25 = ( NH4 + NIT + SO4 ) * 1.10

BCPI
BCPO
( OCPO + ( OCPI 1.05 ) ) (OM/OC ratio) # OM/OC ratio = 2.1 by default
DST1 + SO4D1
(DST2 + SO4D2) * 0.30 # F. Yu suggests 30% of DST2 (Nov 2011); prior value was 38% of DST2
SALA * 1.86
SOA * 1.05"

however, I am still not sure about this question.

thank you.

theloniuspunk commented 2 years ago

Hi,

No, what I'm saying is to do PM25 = ( NH4 + NIT + SO4 + SO4D1 + SO4D2 0.30 ) 1.10 ...

Jeff

lixiao-bit commented 2 years ago

Thanks for hearing from you.

I got it.

so, what is the correct way for calculating PM10?

This is the way for PM10 on the website: "PM10 = PM2.5

( DST2 * 0.7 )
DST3
( DST4 * 0.9 )
( SALC * 1.86 ) # NOTE: The value of 1.86 is the SSA_GROWTH factor at 35% RH"

therefore, Should this be the correct way to calculate PM10 ? "PM10 = ( NH4 + NIT + SO4 + SO4D1 + SO4D20.30 ) 1.10 +

( DST2 * 0.7 )
DST3
( DST4 * 0.9 )
( SALC * 1.86 ) # NOTE: The value of 1.86 is the SSA_GROWTH factor at 35% RH"

"PM10 = ( NH4 + NIT + SO4 + SO4D1 + SO4D20.30 ) 1.10 +

( DST2 * 0.7 )
DST3 + SO3D1
( DST4 * 0.9 ) + ( *_SO4D4 0.9_** )
( SALC * 1.86 ) # NOTE: The value of 1.86 is the SSA_GROWTH factor at 35% RH"

thank you.

theloniuspunk commented 2 years ago

Still need the 1.1 inorganic growth factor @.***% RH) for the SO4D species:

PM10 = PM2.5 + ( SO4D2 0.7 + SO4D3 + SO4D4 0.9 ) * 1.10 +

( DST2 * 0.7 )
DST3
( DST4 * 0.9 )
( SALC * 1.86 ) # NOTE: The value of 1.86 is the SSA_GROWTH factor at 35% RH

lixiao-bit commented 2 years ago

thank you. i got it.

yantosca commented 2 years ago

I will close out this issue. Feel free to open a new issue if you still have problems or concerns.