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==Platinum-group metals== | ==Platinum-group metals== | ||
{{sum|Problem in some cases}} | {{sum|Problem in some cases}} | ||
'''Tl;dr:''' [[ | '''Tl;dr:''' Too many [[fuel cell vehicles]] '''would''' be a problem. Hydrogen production would '''not''' be. | ||
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Burning hydrogen gas in air produces nitrogen oxides (NOx) in the same amount as burning gasoline or any other fuel. This happens because air is 78% nitrogen gas and 21% oxygen gas - any high temperature will cause some of the nitrogen to react with the oxygen. NOx gases are [[greenhouse gases]]. | Burning hydrogen gas in air produces nitrogen oxides (NOx) in the same amount as burning gasoline or any other fuel. This happens because air is 78% nitrogen gas and 21% oxygen gas - any high temperature will cause some of the nitrogen to react with the oxygen. NOx gases are [[greenhouse gases]]. | ||
For [[hydrogen combustion vehicles]], this problem can be solved the same way it is for gasoline or diesel combustion: The vehicle has a ''catalytic converter'' to convert these gases into harmless substances. This requires some platinum-group metals ([[# | For [[hydrogen combustion vehicles]], this problem can be solved the same way it is for gasoline or diesel combustion: The vehicle has a ''catalytic converter'' to convert these gases into harmless substances. This requires some platinum-group metals ([[#Platinum-group metals|see section above]]). | ||
==Atmospheric losses== | ==Atmospheric losses== | ||
{{sum|Very minor}} | {{sum|Very minor}} | ||
'''Concern:''' When hydrogen gas leaks into the atmosphere, it's so light that it ends up being lost forever into outer space via [//wikipedia.org/wiki/Jeans_escape Jeans escape]. If this goes on for ''long enough'', could Earth lose enough hydrogen that | '''Concern:''' When hydrogen gas leaks into the atmosphere, it's so light that it ends up being lost forever into outer space via [//wikipedia.org/wiki/Jeans_escape Jeans escape]. If this goes on for ''long enough'', could Earth lose enough hydrogen that this would harm ecosystems or deplete the global water supply? How long would that take exactly? | ||
'''Answer:''' If we assume: | '''Answer:''' If we assume: | ||
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* that losing '''0.1%''' of the world's oceans would be enough to be a problem, | * that losing '''0.1%''' of the world's oceans would be enough to be a problem, | ||
* that hydrogen gas would be replacing '''all''' fossil fuels, by energy, | * that hydrogen gas would be replacing '''all''' fossil fuels, by energy, | ||
Then it would take a '''million''' years to have even a minor effect on the ecosystems: | Then it would take more than a '''million''' years to have even a minor effect on the ecosystems: | ||
<tab name="(see maths)"> | <tab name="(see maths)"> |