From: Spudboy100@aol.com
Date: Thu Jun 12 2003 - 18:18:55 MDT
http://www.wired.com/news/autotech/0,2554,59220,00.html
...But in the Science article, researchers at the California Institute of Technology raised the possibility that a hydrogen economy will not necessarily be a totally environmental friendly one.
Their study says that if hydrogen fuel replaced fossil fuels entirely it could be expected that 10 percent to 20 percent of the hydrogen would leak from pipelines, storage facilities, processing plants and fuel cells in cars and at power plants.
Because hydrogen readily travels skyward, the researchers estimated that its increased use could lead to as much as a tripling of hydrogen molecules -- both human-made and from natural sources -- going into the stratosphere, where it would oxidize and form water.
"This would result in cooling of the lower stratosphere and the disturbance of ozone chemistry," the researchers wrote, resulting in bigger and longer-lasting ozone "holes" in both the Arctic and Antarctic regions, where drops in ozone levels have been recorded over the past 20 years. They estimated that ozone depletion could be as much as 8 percent.
The loss of some of the Earth's ozone layer is of concern because ozone blocks much of the sun's ultraviolet light, which over time can lead to skin cancer, cataracts and other problems in humans.
Ozone depletion has been contained with the banning and phaseout by international treaty of ozone-killing chlorofluorocarbons, or CFCs. But the Caltech researchers said huge increases in the concentration of hydrogen in the stratosphere "could substantially delay the recovery of the ozone layer" as a result of CFC controls, even if a hydrogen economy is still decades away.
John Eiler, an assistant professor of geochemistry at Caltech and one of the article's authors, acknowledged there remains much that is not fully understood about the hydrogen cycle. For example, much of the leaking hydrogen might become absorbed in the soil, instead of drifting into the sky.
"If soils dominate, a hydrogen economy might have little effect on the environment. But if the atmosphere is the big player, the stratospheric cooling and destruction of the ozone ... are more likely to occur," said Eiler....>>
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