Heterogeneous Reactivity of HCl on CaCO3 Aerosols at Stratospheric Temperature

[Geoeng Info]

https://pubs.acs.org/doi/abs/10.1021/acsearthspacechem.1c00151

Heterogeneous Reactivity of HCl on CaCO3 Aerosols at Stratospheric Temperature

• Han N. Huynh
 and 
• V. Faye McNeill
• 
  
• 
  
• Abstract

Recently proposed as a possible alternative to sulfate particles for stratospheric solar radiation management (SSRM), calcite (CaCO3) aerosols have been modeled to have minimal negative impact on both stratospheric ozone level, through heterogeneous chemistry, and stratospheric temperature. However, the heterogeneous chemistry of CaCO3 aerosols with relevant trace gases, such as HCl, at stratospheric conditions is still underexamined. We studied the kinetics of HCl uptake on airborne CaCO3 aerosols at stratospheric temperature, 207 ± 3 K, by performing experiments under dry conditions using an aerosol flow tube coupled with a custom-built quadrupole chemical ionization mass spectrometer (CIMS) for HCl detection. The reactive uptake coefficient for HCl was measured to be 0.076 ± 0.009. This exceeds the reactive uptake coefficient of 0.013 ± 0.001 that we previously reported for this system at 296 K, consistent with the expected negative temperature dependence of gas uptake on solid surfaces. This finding suggests an initial strong reactive uptake of HCl gas on CaCO3 aerosol surfaces in the stratosphere

[Greg Rau]

2HCl + CaCO3 ---> CaCl2 + CO2 + H2O.   How is this a good thing for GHGs and GW?

Greg

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[Kevin Lister]

I would doubt that there is enough HCl in the atmosphere to make this a significant contributor to the overall CO2 imbalance. 

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[Daniele Visioni]

There have been volcanic eruptions in the past with a 

significant co-emission of halogens.

See for instance this recent study https://acp.copernicus.org/articles/21/9009/2021/acp-21-9009-2021.html

So in a similar case (unlikely but possible) this would matter.

On 3 Aug 2021, at 18:19, Kevin Lister <kevin.li...@gmail.com> wrote:



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