impacts of nanoparticle sodium chloride particles at high altitude

[david....@carbon-cycle.co.uk]

I am seeking to understand what might be any adverse impacts of delivering salt particles of 20 to 50 nanometres to the high atmosphere (greater than 20 km). The salt particles would be derived from sea water and therefore contain other sea minerals. It is worth pointing out that such particles already exist at this altitude derived from sea sprays.  I do not understand the impact of these current particles but I suspect others have already looked at this. I would like to tap into this work.

 

For this discussion, please can we leave aside how these would be delivered to this altitude. I want input on the impact of the fine salt particles and not the delivery.

 

 

David Sevier

 

Carbon Cycle Limited

248 Sutton Common Road

Sutton, Surrey SM3 9PW

England

 

Tel 44 (0) 208 288 0128

 

[Keutsch, Frank N]

Hi,

 

Introducing chlorine in any form into the stratosphere has potential to greatly affect stratospheric ozone. Nitric and sulfuric acid will liberate HCl from NaCl and this HCl can turn into active forms of chlorine. The chloride in solid NaCl itself can react with ClONO2 to form Cl2 which will destroy ozone. So overall, NaCl is not an ideal material for stratospheric aerosol…

 

There is not much sea salt aerosol in the stratosphere. Mostly it is sulfuric acid (with some nitric acid depending on conditions such as temperature) and in the lower stratosphere organic and biomass burning aerosol.

 

Frank

 

 

 

___________________________________________________________________________________________

Frank N. Keutsch

Stonington Professor of Engineering and Atmospheric Science

 

Harvard John A. Paulson School of Engineering and Applied Sciences 

Department of Chemistry and Chemical Biology

Department of Earth and Planetary Sciences

Harvard University

12 Oxford Street

Cambridge, MA 02138

USA

 

E-mail: 

keu...@seas.harvard.edu

 

Tel:+1-617-495-1878

___________________________________________________________________________________________ 

--
You received this message because you are subscribed to the Google Groups "geoengineering" group.
To unsubscribe from this group and stop receiving emails from it, send an email to geoengineerin...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/020201d94ad2%242f00a7e0%248d01f7a0%24%40carbon-cycle.co.uk.

[david....@carbon-cycle.co.uk]

Dear Frank,

 

Regarding your comments, I have a few questions and comments.

 

I can see that your point about chlorine but this will be dependent upon the rate of reaction. Do you have any data on reaction rates? Do you have any data of potential impacts of the height on reaction rates?  I suspect height could have a major impact as the concentration of both nitric and sulphuric acid will be different.

 

I would also like to see data on the predicted concentrations of sodium chloride across the air column and if there is data on how position on the globe affects this. I am asking because if we are only increasing the salt concentration at a given height by overall a few percent compared to the natural background level, then this becomes a minor discussion. Obviously lower heights will mean lower residence times, but an understand of this issue will allow determination of the sweet spot where the greatest SRM effects are delivered for the lowest negative impact.

 

Potentially, alternative solid salts could be delivered such as sodium sulphate which is a common industrial waste product. Cost would be higher than sea salt. Neither option will have anywhere near the costs that using SO2, H2S, or sulphuric acid would attract due to handling and storage issues.

 

Regards,