Phase transformations in sulfuric acid aerosols: Implications for stratospheric ozone depletion
- Environmental Chemistry Division, Department of Applied Science, Brookhaven National Laboratory, Upton, New York (United States)
Activation reactions of benign chlorine species (HCl, CIONO{sub 2}) on aerosols in the winter polar stratosphere set the stage for the spring-time catalytic destruction of ozone leading to the Antarctic ozone hole. Field observations have demonstrated the existence of both solid and liquid particles consisting of H{sub 2}SO{sub 4}, HNO{sub 3}, and H{sub 2}O. The exact freezing conditions and final composition of the solid aerosols remain the subject of investigations. We present laboratory observations of isolated individual sulfuric acid/water particles under stratospheric temperatures and water vapor pressures. Our experiments demonstrate that this binary system would not freeze unless temperatures were below the water-ice frost point. Upon freezing, we observe H{sub 2}SO{sub 4}{minus}8H{sub 2}O, not the generally invoked H{sub 2}SO{sub 4}{minus}4H{sub 2}O. We suggest that the water-rich octahydrate phase is likely to be one of the high relative humidity forms which is efficient in chlorine activation.{copyright} 1997 American Geophysical Union
- Research Organization:
- Brookhaven National Laboratory
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 534441
- Journal Information:
- Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 1 Vol. 24; ISSN GPRLAJ; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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