Quote:HCl is primarily found in the troposphere, its source is ocean salt sprays. That is correct, but its presence in the Chlorine cycle is ephemeral. HCl readily dissolves in the presence of water vapor, therefore there are no significant quantities of HCl in the statrosphere, the area where Ozone formation takes place.



2. THE CHLORINE CYCLE


2.1) What are the sources of chlorine in the troposphere?


Let us divide the chlorine-containing compounds found in the

atmosphere into two groups, "organic chlorine" and "inorganic

chlorine". The most important inorganic chlorine compound in the

troposphere is hydrogen chloride, HCl. Its principal source is

acidification of salt spray - reaction of atmospheric sulfuric and

nitric acids with chloride ions in aerosols. At sea level, this

leads to an HCl mixing ratio of 0.05 - 0.45 ppbv, depending strongly

upon location (e.g. smaller values over land.) However, HCl dissolves

very readily in water (giving hydrochloric acid), and condensation of

water vapor efficiently removes HCl from the _upper_ troposphere.

Measurements show that the HCl mixing ratio is less than 0.1 ppbv at

elevations above 7 km, and less than 0.04 ppbv at 13.7 km.

[Vierkorn-Rudolf et al.] [Harris et al.]

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