Researchers from the California Institute of Technology raised the possibility in a report 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 into the stratosphere and indirectly cause increased depletion of the ozone. The new technology could lead to greater destruction of the ozone layer that protects Earth from cancer-causing ultraviolet rays.
Because hydrogen readily travels skyward, the researchers estimated that the increased use could lead to as much as a tripling of hydrogen molecules — both manmade and from natural sources — going into the stratosphere, where it would oxidize and form water. The researchers also acknowledged that much is still unknown about the hydrogen cycle and that technologies could be developed to curtail hydrogen releases, mitigating the problem. However, they say hydrogen's impact on ozone destruction should be considered when gauging the potential environmental downside of a hydrogen-fuel economy.