By Jim Scanlon
Once again the main-stream and scientific press and broadcast media are silent on a new study by a well-known Noble Prize winner which points to yet another threat to the stratospheric ozone layer. Exhaust gases and aluminum oxides from solid-fueled rocket motors used by NASA's Space Shuttle, Titan IV, and other launch vehicles, combine in the mid latitude stratosphere to liberate chlorine-destroying ozone.
Nobel Prize winner Marie J. Molina with his wife and three other scientists from the Massachusetts Institute of Technology performed laboratory experiments simulating the temperature, humidity and pressure found in the lower stratosphere and discovered that chlorine nitrate (CIONO2) and hydrogen chloride (HCI) react on particle clusters of aluminum oxide (AIO3) to form nitric acid and free chlorine (CI2). Free chlorine very effectively catalyzes the destruction of ozone. Since ozone adsorbs short wave ultraviolet radiation, its absence allows this form of sunlight to penetrate deeper into the biosphere where it can harm living things.
The report, "The reaction of CIONO2 with HCI on aluminum oxide," appeared in Geophysical Research Letters, Vol. 24 No 13, July 1, 1997. The authors stressed the impact of their findings on space launch vehicles using solid-fueled rocket motors such as the Space Shuttle. The main exhausts from these booster rockets are alumina particles, HCI, and water, along with smaller amounts of chlorine and carbon monoxide and dioxide.
Previous scientific estimates of the effect of solid-fueled rocket motors on stratospheric ozone have considered only the ozone depletion potential of the small amounts of chlorine released and the inefficient liberation of chlorine on sulfuric acid droplets. This study, reporting a much more efficient process for the production of chlorine on alumina clusters, implies that the impact of the Shuttle and other launch vehicles will have to be re-assessed and upgraded.
About two thirds of these emissions are deposited in the troposphere where they are quickly removed by changing conditions. The other third is deposited in the relatively stable, unchanging stratosphere where they can remain for months, or even years.
Scientists have measured large increases in aluminum particles in the lower stratosphere from 1976-1984 and attributed this change to solid-fueled rocket motors from space launches and thermal insulation paint used on space craft.
The number, type, and variety of space launching continue to increase yearly. NASA plans 42 Shuttle launchings in connection with the Space Station alone and there are, at present, at least two separate plans to launch large number of low earth-orbit communications satellites to provide global cell phone coverage.
Computer models suggested that ozone depletion would be localized along the exhaust vapor trail, and satellite observations (which scan large areas) seemed to support this by reporting no observable widespread ozone loss. This is now cast in doubt.
It appears that the nature of the metal found in the clusters is not important for the reactions to take place, so it would seem that other metals found to be rapidly increasing in the stratosphere would be just as effective as aluminum. Water seems to play a crucial role in coating the surface of the clusters to allow the heterogeneous reactions which liberate chlorine. It would seem that water is as destructive to the stratosphere as acid, toxics, or oil spills are to the surface.
Heterogeneous reactions on ice surfaces are responsible for the release of chlorine in the Antarctic Vortex which results in the almost total destruction of all ozone in the lower stratosphere. The aluminum oxide process is not expected to worsen ozone depletion at the poles since the reactions on polar stratospheric clouds are much more efficient-that is, things can't really get worse there!
However, the alumina process can take place at mid-latitudes where polar stratospheric clouds can not form. Since mid-latitudes get, on average, much more sunlight than high-latitudes, increasing depletion in ozone can be expected to allow more ultraviolet to penetrate lower into the biosphere.
Finally, the question remains as to what constitutes "news" in America, a society inundated with information. With the findings of a world-famous Nobel Prize Winner, an American of Mexican descent working with his wife and a team of scientists in one of the world's top scientific institutions, uncovering facts which raise serious doubts about global environmental effects of the highest of the high-tech space and satellite programs-one would think that such a subject merited mention somewhere else in addition to the Coastal Post.