The report says government efforts to control emissions of reactive nitrogen from combustion sources have been more successful.

BBC: Nitrogen pollution 'costs EU up to ?280bn a year'

These, he says, are 1, 500 times better than existing sensors at detecting hydrogen. (The gas combines with the tubes, changing their electrical properties.) Hydrogen detection is used to help control certain processes in industrial food production, for tweaking fuel combustion in car engines, and in monitoring certain bacterial infections.

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