University of Cambridge > Talks.cam > Centre for Atmospheric Science seminars, Chemistry Dept. > Chlorine activation and enhanced ozone depletion induced by wildfire aerosol

Chlorine activation and enhanced ozone depletion induced by wildfire aerosol

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact lj384.

Remarkable perturbations in the stratospheric abundances of chlorine species and ozone were observed over southern hemisphere mid-latitudes following the 2020 Australian wildfires. These changes in atmospheric chemical composition suggest that wildfire aerosols affect stratospheric chlorine and ozone depletion chemistry. Here we propose that wildfire aerosol containing a mixture of oxidized organics and sulfate increases hydrochloric acid solubility and associated heterogeneous reaction rates, activating reactive chlorine species and enhancing ozone loss rates at relatively warm stratospheric temperatures. We test our hypothesis by comparing atmospheric observations to model simulations that include the proposed mechanism. Modelled changes in 2020 hydrochloric acid, chlorine nitrate, and hypochlorous acid abundances are in good agreement with observations. Our results indicate that wildfire aerosol chemistry, while not accounting for the record duration of the 2020 Antarctic ozone hole, does yield an increase in its area, and a 3-5% depletion of southern mid-latitude total column ozone. These findings increase concern that more frequent and intense wildfires could delay ozone recovery in a warming world.

This talk is part of the Centre for Atmospheric Science seminars, Chemistry Dept. series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.

 

© 2006-2024 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity