Stratospheric Aerosols Physicochemistry

Bricard, J.; Vigla, D.

doi:10.1139/v74-219

Cited by 9 publications

(1 citation statement)

References 13 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Lidar experiments and collection experiments with filter papers have both indichted the presence of stratospheric aerosol particles, especially in the 15-to 20-km range a few kilometers above the tropopause [e.g., Junge et al, 1961;Hoffman, 1974;Bricard and Vigla, 1974]. The presence of these condensed phase particles raises the possibility of heterogeneous surface reactions in the stratosphere, either for the chlorofluoromethanes themselves or for their photodecomposition products.…”

Section: Aerosol Particles In the Stratospherementioning

confidence: 99%

Chlorofluoromethanes in the environment

Rowland

Molina

1975

Reviews of Geophysics

673

252

View full text Add to dashboard Cite

The molecules CF2Cl2 and CFCl3 are released into the atmosphere following their extensive use as propellants for aerosol spray cans and in refrigeration. Since they are chemically inert and have low solubility in water, these chlorofluoromethanes have very long atmospheric residence times and can be detected throughout the troposphere in amounts roughly corresponding to the integrated world industrial production to date. The most important sink for atmospheric CFCl3 and CF2Cl2 appears to be photolytic dissociation in the stratosphere by ultraviolet radiation around 2000 Å. Upon photolysis the chlorofluoromethanes release chlorine atoms, which initiate an extensive catalytic chain reaction Cl + O3 → ClO + O2 ClO + O → Cl + O2 leading to the net destruction of O3 in the stratosphere. This chain reaction can be diverted through reaction of ClO with NO, which interconnects the NOx and ClOx catalytic cycles. The Cl‐ClO chain is interrupted by the reaction of Cl with methane or other hydrogenous species to form HCl, and it is renewed by reaction of OH with HCl. One‐dimensional diffusion calculations show that present O3 depletion levels resulting from the presence of the chlorofluoromethanes are of the order of 1%. This depletion would increase up to 15 or 20% if the chlorofluoromethane injection were to continue indefinitely at present rates. Furthermore, the calculations show that the full stratospheric effect of the photodissociation of CF2Cl2 and CFCl3 is not immediately felt after their introduction at ground level because of the delay required for upward diffusion to the 25‐ to 30‐km level. If the atmospheric injection of these compounds were to terminate only after causing an observable depletion of stratospheric ozone, the depletion would intensify for sometime thereafter and would remain significant for a period of a century or more.

show abstract

Section: Aerosol Particles In the Stratospherementioning

confidence: 99%